ok girls, here is my 2c worth. I am 112kgs atm and pg. I never have had a problem falling pg. I've had 6pgcies all up. Granted I lost 3 but conversly that was when I was at a healthish weight range! I honestly believe that was stress induced. When I married Dh, I'd put on 10kgs in the six month prior and BANG, I was pg. I had DD#1 (had gained another 17kgs)and fell again within a cycle. I had DD#2 and had IUD put in which caused me problems no end (INCLUDING weight gain). I finally got that sorted in feb/march when it burst and the next cycle that DH managed to score a goal within the lines (we weren't timing DTD as he wasn't quite ready), I'm pg again! Size doesn't matter for some people. My mother is another one who is and always has been overweight and she fell every time she looked at my dad.
However, when I have u/s's they cannot see my c/s scars at all (I had two and they said during last one that everything looked dandy down there and I could have as many as I wanted!). I am seriously thinking it is the scarring causing your problems honey. You can fall pg, maybe go to OB and talk to him about your worries. Ask him to check scarring and what he thinks. I seriously think that is the way to go honey. Don't beat yourself up over the eating hon, we all do it at times. *hugs*. We all have our weaknesses.