You are eating too few calories. it isnt a good idea to go under 1200 cals a day..it isnt healthy for you you wont get the nutrients you need. I dont know your weight but depending on how overweight you are you may need MORE than 1200 cals.
I suspect your body has decided you are starving it and refuses to let any weight go. Did you put all your information into Sparkpeople and get a calorie recommendation? That would be a good first step if you havent. go to your Start page and enter your information..it will give you a calorie range. i'm betting when your body is getting the fuel it needs you will see a loss!