I think that I am a horrible person
Tell me why you that
I never do nice things for anyone.
While that doesn't necessarily make you a horrible person, it is quite selfish to not be available for other people. You need to make the appropriate changes in your behavior, and be nicer to people so that you will be liked more.
I don't care if people like me or not.
But even if you are not concerned about their reactions, it sounds like you are concerned about how you view yourself.  If you want to be a better person, you should do nice things for others, even if you won't get anything out of it.  It will help you feel better.