1200 calories & running

I just started running 2-3 miles again. My goal is to lose 15-20 more pounds. I've already lost 14 in the past two months from eating between 1200 & 15 calories daily. I usually binge a couple times a week and eat pizza and ice cream and other stuff I crave occasionally. My question is, will it damage my metabolism to eat only 1200 most days if I'm running 3 miles daily? Keep in mind, a couple days a week, I'm having one meal of cheat food. Haha another question too- has anyone had god weightloss while having a couple cheat meals each week? Any tips appreciated. Thanks!