I'm so bitter that I have nothing good nothing that gives me happiness and that the man I have interacted with didn't care about me at least as a human being
Why do you feel so bad about yourself?
Just because I have nothing which makes me happy.
If you are feeling stressed or sad, there are things that you can do to help feel better quickly. Communicate with friends and learn to appreciate what you have rather than what you don't have.
I hate that. I hate people who are positive and happy.
It sounds like you are still bitter about what happened with the man in your life. You should seek therapy to help you resolve those issues.