I have to ask --- do you love yourself? If you don't love yourself, then perhaps, you have a hard time accepting love when it is given to you.
It's not easy if you've been through a lot as a child and as a young adult---especially if your self-esteem and self-confidence has been battered. However, you can start by telling yourself all the things you love about yourself. Say it out loud or put it to paper. I'm sure you can think about all your good qualities. Do this on a daily basis and you will start to feel better about yourself. It won't happen overnight but if you stick to it, each day will be better than the last.
In the meantime, don't get into another relationship until you are sure you are ready to give and accept love.