I have an eating problem

I had a baby 5 months ago. I’ve lost over 50 pounds since giving birth. These last 2 months I’ve stayed the same weight and this past week I’ve gained 5 pounds. I wasn’t eating at all pretty much. I was so eager to lose weight. I’ve always been obese and something in me was tired of it. Now I can’t stop eating. I know it’s probably because I’m mentally not doing good. I also know it’s not the best, but when I didn’t eat I’d drink a diet Dr Pepper when I felt like binge eating. I was thinking about doing that again.