This does not make sense, impossible if you were doing proper nutrition. Obviously your nutrition is wrong. do you have a spread sheet of everything you ate. Myplate does this.

Track your meals with one of the online calorie counters. Everything that goes in your mouth make sure you log it to see just how much you're eating. It's possible that even though you're eating incredibly healthy that you're overeating.

Also, like a couple said you want to do 6-10 reps max. You need to build the muscular core that'll burn all that extra fat away. It'll equal short term weight gain but you should see changes to how your clothes fit far sooner than the scale will tell you anything.