I lost 11lbs in the two weeks before surgery, and then another 21lbs in the one month immediately following surgery. Nobody noticed! But of course, I noticed in terms of clothes getting looser.
At my 7 month post op mark (I'm at 10m po now), losing 3 lbs would have others telling me how worried they were for my health.
It's all relative.
Like the others have said, take pictures. And keep track of your measurements, it's a great motivator down the road ❤️