I'm four weeks post-op as well. Net weight lost since surgery is 21 lbs. and seems to have stalled at 204. But I have a scale that measures body fat and muscle weight and I see that while I'm losing fat, I'm also gaining muscle (I'm working out regularly for the first time in a long time). The muscle gain nearly cancels out the fat loss in pounds. So I try not to despair too much.
At my last visit to the clinic, someone who was seeing me mentioned that our protein levels (thus muscle) takes a deep dive just after surgery. I think the body needs a lot of protein to heal and rebuild.
Hang in there! As long as you're doing the program, you're getting healthier and likely losing a lot more fat than you think you are.