Darl, I dunno how old you are but you do look pretty young...
The benefit of that is your body will fix itself, But you have to give it time, Ava is only 3 months?! (i think!) it takes 6 months just for your womb to go back to its normal size...
It took you 9 months to grow your little girl, its going to take around the same time for you to recover from it. Your a young healthy girl, I know its hard but try not to get too torn up about it.
As for the FOB situation, What kind of life is he really having? Is going out and getting "stoned", drunk till you pass out and having no recolection of the things you've done really much of a life?
I see things plastered all over facebook from people i used to go to school with and just think WTF? Why... surely feeling like your dying the next morning isnt worth it?
Anyway i digress!!
Your doing fine, You'll continue to do fine! Give yourself a break and a chance to be the mum that you know you will be! xxx