I was taught that a weight loss stall is three weeks without changes to scale weight or size. I am just at week 4, and have lost about 12 or 13 pounds since surgery. So by the definition that I am using, no I haven't had any stalls. I have had days I did not lose anything on the scale and days that the scale bounced upward instead of down. And then I have stretches where the scale shows a pound down every day. Pre-Surgery or post surgery, weight loss before and during the week of my period is impossible. It just does not happen.
I think something that helps me stay sane is that I believe weight loss is not linear. On a given day you can eat exactly the right amount of calories to lose, drink all your water, and exercise, but the scale the next morning may not give you a loss. But if you stay the course over time, you absolutely will lose weight/fat/mass.
Lucky you for that exercise clearance! I am looking forward to working out, especially almost 40 lbs lighter than I was when I started the pre-op diet.