I think my life is one sick joke and I'm the punchline
Why do you think your life is a sick joke?
Because of all the shit that these jerks put me through.
I understand how you're feeling because life can be cruel sometimes, but it's good to remember that things will get better. I think you should forget about those jerks and try to move on to bigger and better things.
You're right, I guess I'll try to be more positive from here on.
That is a good first step. You can make your own happiness as long as you stay positive. Ignore the others and find people who share your own feelings.