I had the same problem and my doctor told me that at the biggining, it will be difficult so get such as you can soon like in the third week you will be able to get it all in.
I been drinking more water and exercising more and started to lose weight again. If you are in a stall try that. I've lost 40.2 lbs and my surgery date was Oct 3.
My surgery was Oct , 3 and after the fluids from surgery I gained the 13 pounds I had lost so from the day of surgery, I've lost 36 lbs but now the weight loss is slowing down and am getting frustrated. Tell me how much have you lost?!