If you really are INTP and seeing as you are 17 life might be rough for a while...just saying. Hopefully some other INTPs can give you some advice here.
As for this relationship, I think you are wise in wanting to cut ties. I think since your feelings are still involved you should at least take a break. Just tell her you need space from her, tell her why, and tell her if she really values you as a friend she will respect your wishes. You might get a chance to talk some things out, but regardless, you're gonna want to take a break else turn even more bitter and curmudgeonly.
If you are entering a depressive phase, for god's sake start taking steps to pull yourself out of it. If you wallow in your depression and misanthropy the rest of your teens and early 20s are gonna be as ugly as you make them. Nobody else but maybe your close family will know that something is 'wrong', they will just assume you hate people and are extremely introverted, and basically there is no cavalry on the way. You are just digging a hole for yourself that is getting harder and harder to climb out of. Don't do it! Get some sunshine! Start chatting with people online if you hate everyone 'in your real life'. Go outside for walks. Hug your cats. Join a D&D group. Find something you like to do then socialize with other people over it. Only you can prevent forest fires!
I think the reason you fell for this girl so hard is that she was kinda the cavalry. If you opened yourself up more and got out there more, you would meet a lot more people like her and have more relationships to sustain you. And redeem your views on humanity and the world.

It's either a positive cycle you start or a negative one, so start the positive one and it becomes a positive self-fulfilling prophecy.
I swear on all things holy, I have kinda been where you've been and once you truly believe that there are people out there for you, it comes true. If you keep telling yourself people suck or no one will understand you or you hate everyone or [fill in negative blank] you will it to happen because you refuse opportunities before they happened.
On that positive note, things can and do get much, much better. Part of it is getting out of a closed environment and entering 'the real world' and discovering yourself and other people.
I'm an ENFP but I had a brutal time in highschool, but I was/am hella freaking extroverted as far as my need for the external world and interaction with people - if I were an introvert, dear god I can only imagine how much harder it would have been. So I feel for ya. For me, I made the mistake of simulating my highschool experience by going to another small, isolated school. Then I learned my mistake and now I head for the high ground (big cities, bright lights, open minds, and non sheep people).
So yeah, learn from this - don't make your life into such extremes because you will end up pinning all your hopes and fears on the first person who slips past your barricades. Open up the gates instead and embrace the world. Or at least a bigger chunk of it than you are now. If you keep on the way you are now, this is just going to happen again, but in between there will be long stretches of self-imposed misery.
Seriously, I have seen/experienced enough INTPs in this negative loop to know what I am talking about. This is all completely preventable.