HELP! Why Am I SOOO Hungry Suddenly?

I dont know what is going on but I have been doing about the 1200 calorie range for around 3-4 months. Its been really good, actually. Ive been doing Nutrisystem and I love it mainly because of ease with my really hectic schedule. The last three days however, I simply cannot eat enough!!! Last night I ate three desserts (they were NS but still) and today about 30 minutes after a snack or a meal, I was hungry again. I have been doing Jillian Micheals Shred and running on the treadmill the last two months. I have really been pretty full at the end of the day but this week I just cannot get full! I am still about 10lbs from my goal so I dont want to up my calories but does anyone have any ideas or solutions for me?? Thanks so much!