I think that you need more than Reiki can give you...
Sometimes, we get into patterns in our lives that we need professional help to break. A good counseler can help with that. There is certainly a mental health center near you. You can also work out the traumas of your past, and get a new, fresh start on life. It takes hard work, but it's worth it.
As for helping others, consider this...your troubles, once you have come to terms with them, will give you the strength and knowledge to help others in your current position later in life. You are a very special person, with a lot to give.
If you are actively considering suicide at this point, please, please, get yourself to a hospital right away.
Roxy