I am 2 months post op VSG and only losing 1 pound per week (my weight loss has been slow like this since day one)?

(my weight loss has been slow like this since day one). I follow all dietary and exercise guidelines from my doctor's. Possible reasons for poor weight loss results? How can I improve the situation? I eat a protein rich, low carb diet, calories under 800 per day. water ,over 100oz per day and my protein ranges from 60-85g per day. 6 out of 7 days I treadmill -speed of 3 miles per hour keeping my heart rate 123-150 bpm. MY STATS: high weight-332.7 , surgery weight 312.6, current weight 287.1lbs