What scale should I believe?

Hi, This seems silly but I was 280 pre-op. I weighed that at the hospital and at home. When I was released Sunday I was 277. Yesterday I weighed myself at home and the scale read 267. Is that possible? I have not been able to drink much but that seems like a lot of weight to lose so fast. Don't get me wrong, it does make me happy. But aren't all scales different? I have my first post-op visit tomorrow. Let's see what that scale reads. Anyone experience this as well? Please send thoughts. Recovering in NJ, Ana