Oh Jessica, don't feel defeated, losing weight is very difficult...I honestly don't think you are eating enough..800 calories is not enough...your body could be in starvation mode and won't let the pounds go...try eating a bit more and see what happens.
The band is designed to make you feel full after just 3/4 cup of food, it does not count the calories for you. You could eat a 3/4 cup of fries vs 3/4 cup of protein or veggies and the calorie count differs quite a bit. You are required to follow a diet plan of protein, veggies, grains and fruit, in that order when you are banded. The protein rich diet helps promote weight loss.
You can do this...it seems difficult now, because your body is not losing, but you must realize that the hard part hasn't even begun yet...the post-op liquid diet will be a struggle too. Liquids only for 3 weeks, no solid food.
Bump up the protein and the calories a bit and see what happens...I find when I eat more protein per day than anything else and stay under 1200, I lose.
Good Luck Sweetie...you can do this!!!!