I understand how you feel. I felt that way most of my life. I had to find a way to do soul searching, read the book The Secret, and turned myself into a positive thinker.
I was NOT easy. It takes a lot of practice and some good support.
When you have a negitive though, stop it right there! Change to a positive thought. this was hard for me at first. it took at least the first week to quit crying and thinking stupid it was. But finally I started to regain control.
Also, you have to realize it is ok to forgive yourself, forgive others and be happy. Most of the time a depressive is not happy, because they feel they are taking away from the problem if they are. Not true.
The ONLY one unhappy is you. no one else is affected. I know this sounds cold, but you have the right to be as happy as you want and do not worry about what others say.
If you try to help someone and they are rotten, forget their opinion and just remember YOU did the right thing.
Please, before you make a final decision, get on medication, change the negitive thoughts and find positive even if it is only to look at the blue in the sky and not think of anything else.
You will still have bad days, but they will be less and less as time goes on.
Let me know it this helps. I will be happy to be a mentor and guide.
I spent most of my childhood and adulthood thinking of suicide.
Now life is fine for me.