I have had the same issue. I lost 20 pounds in the first week after surgery, then after that I was just gaining and losing the same 5 pounds...then 3 pounds and now I'm just stalled. 24 pounds down for month 1. I am just now entering my second month and I log everything I eat and drink. I usually net about 400-600 cals a day. I started just walking a mile or 2 after dinner and it seemed to help, also I was not drinking enough water, so I've been making it a point to just keep a 40 oz bottle on hand and sip all day, and refill once more and sip all evening.
I've been in this gain/loss/stall since Oct. 5th actually. But the inches are definitely coming off! Log everything, and eventually it will break the stall I think! I'm telling myself that everyday at least.