For some reason I didn't have much bloat at all. I think it's because I was only in the hospital about 24 hours so I didn't have the days and days of IV fluid. I'm assuming that it's fluid...my "significant other", who was my recipient, came out of the surgery weighing 6 lbs more than when he went in, despite the fact that he had two 12 lb kidneys removed in the surgery. He was bloated for about a week and a half after discharge, and then he started peeing out liters and liters every night, losing 5 lbs over night every night for a few, until he was down a total of 24 lbs from pre-surgery weight.
So, in other words, it's probably just fluid, and yep, you will start losing it soon.