As far as which needs aren't being fulfilled...I'd say first and foremost the passion for a subject. I enjoy philosophy, but more in the realm of discussing it with others and debating it, which brings me to the second thing...I have no person that cares about me in a non-physical well being sense, no person that respects me, and no person that I can discuss my ideas with. INTPs I think benefit a lot from having a few friends they can go to and say, "Hey, I figured this out and..." I have had only 1 such friend ever. I want to say that going back to college would fulfill that...but it never fulfilled that before (maybe just the wrong college...Oklahoma State is like 40% business majors, 15% agriculture, 10% biology, 10% engineering, 10% education...etc...I think I was one of about 40 philosophy majors out of about 20k students when I went there). Perhaps if I transferred over to OU (which is like 60% social sciences, liberal arts, and education) I might be more likely to meet people...but I wouldn't get my hopes too far up. Oklahoma is not a good state, as far as culture, for an INTP, but I can't afford an out of state college (or even in state atm :/).
I have to agree. College can suck so bad for INTPs because they make you take so many seemingly useless and crappy classes. My big hatred was foreign language, as I deemed it completely retardedly useless for a philosophy major. Let people translate philosophy into English and I'll read that. OSU required 10 credit-hours of foreign language too :/
As far as trusted family members...I don't trust a single person that I know personally. Most of them despise me...they're almost all sensors, and I've never gotten along with sensor types ever.
Harmony with other types
I HATE SJs. They are fucking absurd, and they are only ever going to be the cogs in society's wheels. Remember that- they are too dumb and obtuse to tap into the iNtuition that we have. I believe (but cannot prove) that iNtuitive are more successful, and are also more able to grasp theories like the MBTI. I know this is borderline racists- but in my defense, sensors perpetuate even more tension based on stupid things like nation, religion, skin color and baseball teams.
However.... showing your hate to sensors isn't the way to deal with them. It just makes it worse. You've been on the receiving end of a lot of judgement, but you need to remember that for there to be harmony you need to be free of judging people too. Maybe "judging" people is the wrong word. Just remember that they're not crazy, they're just different.
I was trying to tell one of my ex-gfs that she was INFP, and she absolutely disagreed with people being put into categories. I tried to explain that it was just a loose definition, and there are still individual differences, but she didn't quite get it. It was clashing with her "everyone is a beautiful and unique snowflake" ideal; so I dropped it. I don't admit that I'm wrong, I just stopped bringing it up. My life has had less conflict when I've learned to just drop issues that aren't really important.
Jobs
What jobs have you had? Also- do you have a car? It sounds unlikely, but if you do I would recommend pizza delivery. You can spend a lot of time alone in your car, listening to the radio. My INTPness made my mental-map pretty good.
Having a job is also just good for interaction. You'll have some assholes around, but just being around people can help you feel a little more balanced. We're introverted, but we still need some social interaction. The togetherness that a coworkers have is good.
You don't have to go back to college immediately. Having a job while you collect yourself would be totally fine, and a GREAT first step.
INTPs <3 INFPs & INFJs
You should go to the INFJ and INFP forums. They are:
http://infp.globalchatter.com/messageboard/
http://forum.infjs.com/
There are plenty of girls, it shouldn't take too much work to start a PM correspondence that turns into a daily IM/email friendship. It would be a good step towards having support, having someone to reveal yourself to. And they care; I've been blessed to have INFPs & INFJs in my life.
There are Ns at college: hiding
I haven't been to the midwest, but I have trouble believing that there won't be some other Ns for you to commiserate with. There may not be as many as the coasts have. :/ But you just have to find them! Just like you, they are going to be hiding from the ridiculous SJ/SP culture. Sure, they might be in stupid clubs like the gaming club or the anime club (apologies to any otakus out there :-P) but if that's what it takes to meet people like you
then that is what it takes.
Go clubs have NTs
Another idea: is there a Go club nearby? If so, go to it. You'll find lots of NTs. Many of them will probably be older, and they might be able to give you help- or at least some much-needed NT/NT interaction. Also, Go is a fantastic game. While playing, if you are much worse, you can simply request for them to talk about the game with you, as you play it. Talking about the theory behind all the moves is wonderful.
Buddhism!
No one else has touched on religion, so I will. You should consider reading about buddhism. I've been reading this great book, "Seeking the Heart of Wisdom", written by two american buddhists. It's helped me find solidarity, and remove the distractions from my life that are causing me harm.
http://www.amazon.com/Seeking-Heart-Wisdom-Meditation-Shambhala/dp/0877733279
Are these really helping?
In a similar style, I have cut down on how many computer games I play and TV shows I watch. They are a great escape, and enjoyable, but the successes in computer games do not translate to anything in the real world. That's not to say you shouldn't enjoy recreation, but you could probably do something a little more productive, like reading and analyzing whatever presents itself to you. When I flex my Ti, Ne and Si in my free time then my college work gets easier, because I'm already accustomed to focusing. I know you can kick yourself into focus-mode, but not using these skills is a slippery slope. Remember the classic neurobio saying: Use it or lose it!
UUs are asburd, but that's okay
You also might considering looking into Unitarian Universalist churches around. Yes, they're a church, but you don't have to believe in anything except forgiveness. (There are atheists that go to my UU group.) I've found a ton of support from my UU group. And since UUs can handle opposing points of view, you're more likely to find Ns there. A common part of small UU meetings is a check in where you talk about your week. It's not as good as counseling or therapy, but it's still damn good to talk about your problems to people who are supportive. Also, it's free.
disclaimer!
I hope you don't think I'm trying to push you too much, or mold you into another version of me. (As you can guess, these are all the things that have had a positive influence in my life.) I just figured I would give suggestions with a shotgun strategy. Best of luck!