feeling lonely...

so i'm always feeling sad. I have friends but I don't feel like anyone really cares about me. I think that if I'm missing and the people around me are together they don't look for me or no one even bother to ask where I am. I always feel like this and it makes me very sad. No one wants to get to know me. I don't if the problem is with me or what. I'm actually friendly and sometimes I inititate the first conversation to have friendships. It's just that I never felt that anyone wants to know about me or no one really cares about me. It's like im not existing! When I feel sad and I actually look sad no one asks me why im sad. I have many friends I just dont feel like I have friends. I also think that I have problems with intimacy with friends because at first I would make someone feel that I really want to be close to them then when they do respond to me I want to move away but I dont want them to move away from me. I share but I dont say everything about myself. I dont know why. I dont have a bitchy attitude in fact im caring. I always feel that if i open up something they would share to other people. Im also not the type of person who likes to hug people but i like to be hug. I also feel like they are not putting to much effort on the friendship I always feel like I'm the one whose putting all the effort. I don't know if I have intimacy disorder or what please help me... thanks in advance