Wow, I can relate to a lot you mentioned. Parents that don't care about and yet very controlling, cutting so you can feel anything other then sadness, no amount of accomplishment will satisfy your parents, no friends....
I can't tell you not to cut and I can't either tell you that your parents really do care because I know those things aren't necessarily possible. But how about going out and finding new friends? Loneliness is a big factor when it comes down to it, maybe you can find new friends. I know it's easier said then done because since my friends moved on with life I didn't look for new friends. But maybe you can go out and meet new people.

Lots of hugs and good luck.