I can relate. I really don't try even when not depressed. I'm friendly with a handful of people at work (though now I am changing to another job, so there goes that), but it's not like we hang out outside of work. I've been going to meetups, and again, all is fine at our activities, but it doesn't go beyond that. I've realized that I don't really know how to go from aquaintence to friend.
I'm so sorry you were treated that way in school. Sheesh, what jerks. I do agree that that lessens in adulthood, though it still does exist. But at least *most* people know how to act better than they did when college/school age. So it's probably worth trying, though I do understand your POV. Once I get done with work and errands, I'm pretty content to just hang out at home drawing or listening to music or watching shows/movies.
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Makes me sick to the heart, Oh I feel so tired. And the way the rain comes down hard, that's how I feel inside.
--The Cure