I hate people.

Sorry that I can't add too much further insight because my advice has pretty much already been stated. To me this does seem like a case of just focusing too heavily on the negative side of things. It's similar to how the news shows which stories to broadcast, they'll focus many more times on the bad stuff than on the good stories, even though there are probably just as many good things going on out there. In a sense, you're constantly exposed to pretty much how everything sucks.

I feel like you're starting to use the disappointments you've had in your past relationships and apply them prematurely/too broadly to all cases and people.

Relationships definitely do get more complicated as you get older. You're treated nicely (for the most part) as a child and a certain level of expectation is created for that as you grow up. But as you get older, people are more apt to take advantage of you and you become more wise to the faults of certain people. However, you don't achieve acceptance of this at the same time you people wise to it, which leads to a conflict between expectations and what's actually going on.

It may be too simple to just say "life doesn't suck as much as you think" and to just "wait it out". But I guess that's what I'm getting at.

Jam it back in, in the dark.