Staying motivated

I am 5'1 and 166 pounds. I was 125 before I got pregnant with my son two years ago, and I'm not going to lie, after I had him I kind of let myself go. I suffered a lot of depression plus I was in an abusive relationship. Now I'm wanting to get my body back. The thing is I don't know where to start, what to eat, or what kind of exercises to do. I just mainly am focused on tightening my stomach, because it's so loose and flabby.😭 Also how do I keep myself motivated? I've tried this several times but just quit because of no motivation.