Why Im not losing??

I'm 34 female 5'6 158 pound . I would like to lose 10 pounds but seems impossible the scales wont move. If I do 1200 calories and Jillian Micheals shread nothing. I must say I lived a low carb lifestyle for 5 yrs and changed to calories last summer. I still watch my carbs while counting calories so I'm eating lots fruits and veggies, low carb wraps,So very limited sugar for the most part. I can sometimes get down a pound or so but having hard time maintaining. So joined Fitness pal just Sunday and its says 1450 calories with my Jillian MicHEALS Shread video 5 times a week. Will I lose weight going up on my calories? Any advice, tips would be Wonderful!! Thanks, Mandy