I don't think you're being a dick by being considerate of your parents. In fact, that shows that you still care for them, despite everything. But at some point you'll probably have to carefully tell your parents how you really feel.

As long as you're not hurting anyone/anything, your mental health is more important than anyone else's approval. If they actually love you, they'll get over it. But if they love the idea of you more than the actual you, then I think it would be completely normal to cut them out of your life, until they come to terms with it. Even if it hurts at first. That's what I'd do, at least.

Also, I get what being lonely is, believe me. At some point I got so sick of it that I went out and joined different hobby groups, even went to a few events that people join specifically to find new friends.

If you do that long enough, eventually you'll find people who've had similar experiences to you, and who you really get along with, who will also want to hang out with you. That at least worked for me.