Wow dude you could be describing me except i have moved on from thinking everything sucks, now i am not sure if you mean life or just doing shyte you don't like. I hate doing things i don't want to. Braai's, family gatherings all that is kuk boring. I did it more when i was with someone to please them but many fights happened because i never wanted to go out all the time.
I was at a mate the other day and his chicks friend was there so my mate tunes her she should date me because i am selfish so we would get along well . The thing is i love doing what i love doing and generally that is chilling on my own doing my thing and it bugs the shyte out of my friends and family but you gotta be true to yourself and wanting to do your own thing is not being selfish. Selfish is turning down a mate when he asks to help him move, if you do that then you are moving into the dick category.
Trust me anti depressants will make you worse, they made me worse. There is no way to fix a loner dude. As much as people will tell you there is something wrong and you should not be the way you are, don't believe it for one second. Be yourself and if that happens to be a loner then so be it. I can tell you though drugs and alcohol do help, it's the only way i can go out because i change into a party animal who never wants to go home but it is bad to do it that way, rather just say no. When my fiancee left me i decided i needed to figure out what i want and i have and i am far happier now that i have accepted that i am loner and if that makes me selfish then so be it.
I think my depression was partly because people were telling me i was suppose to be this way or that way but when i realized i am who i am and people can F right off it changed my life . Of course it helps if you are happy being alone, if that bugs you then you are in trouble. I used to get upset thinking about being alone but i enjoyed it, it would just make me upset until i got into positive thinking and realized i love being a loner and i stopped letting people get to me when they said it's not normal to stay in so much.
If you made it this far

check the link below, that chick is amazing. She just screams positive energy and she helped me big time. It's not just about love check her video's even if you don't think they apply.
http://www.youtube.com/user/carolinlovecoach?feature=g-all-bul she is a lovecoach but she is more of a live coach and the positive energy she brings to the table is amazing. Changed me from a negative cynical person to happy, positive person. Still a loner but much happier.