What do you think of me being too bitter and not feeling happy for other people anymore?
That's not good. Do you blame other people for your bitterness and inability to feel happy for others?
No, I've been miserable for a long time.
I understand how you're feeling, but carrying around all that bitterness and anger isn't good for you. I think you should talk to a professional who can help you deal with your emotions.
My friends already tried to, man. Nothing seems to help me get out of my misery.
Even though they tried, they are not trained in that. You should seek some professional help so that you can manage your feelings better. It is better for your health.