Hi, so sorry you are hurting. Change is hard but usually for the better when you are committed to have a better life, feel better, etc. Start small but be persistant. Weight problems? Change your diet. Not all at once, but slowly replacing bad food (caffeine, alcohol, sugar, processed food, junk food) with good whole food. Every other day, do at least 10 - 15 minutes of physical exercise or just walk. Two website that offer some really good "food for thought" on taking care of yourself and letting go of the past: Attitudinal Healing (Dr. Jerry Jamosky (spelling?) and DoctorYourself (Andrew Saul).
We all make bad choices in life, let it go or it will make for a miserable life. The past is gone and has no power over you anymore unless you let it. The future is not here yet, so what can you do to make it better than where you are in your life right now?
So lets see where you could end up in the near future: healthier, slimmer, more wise about choosing a mate, happier? Those sound like good choices to me. They can be done, I am living proof.
I have faith in you but you must have faith in yourself. Nothing is impossible, nothing.
Good luck to you, sending good vibes your way.