Dear Pet,
Without knowing more about you,it's hard for me to give you some good advice.
But first,I am sure that you are right.You said that nobody would care if you left home.What about your parents?And other family members?It seems that you are very sad.You'd better go to a doctor or talk to your parents.They will be able to help you.
Second,I'm sure there's someone else in your class who feels lonely,too.You never know how other people feel.Try to make friends with your classmates.And you could join a club to meet new people and make friens,too.
You last find happiness in yourself.So my last advice is to write a list of all the good things about yourself,learn to like yourself,and then others will see your confidence and like you,too.
急啊!!如果有打错的,亲自己看着办吧!在线等!!