Stalls happen. And most commonly at the 3 week post op mark. Suggestions, keep doing what you are doing. Make sure you are hitting your water intake, everyone posts about their food, but almost never about their water, your body CAN NOT process fat without enough water to do so... so make sure you are getting 64-128oz of water (Or as much as you possibly can right now) And you haven't stated your current exercise regimen. You should be walking pretty much once and hour, get into the habits now, it makes them easier later on. Don't worry about stalls, and do not focus ONLY on weight. You can lose body fat and not lose any actual weight. I've been stuck around the same weight for more than a week, but I've lost .7% body fat in that time. So, don't stress and don't get frustrated (not easy, I'm fully aware of that!)
Just keep doing what you are supposed to be doing and you'll be fine.