I only lost about 6.5 pounds.
I remember of doing some reading about fasting some time ago on a different forum. Fasting can be a really good thing. But there is some math involved for the amount of bodily fat that a person can consume in a typical day of fasting which is probably less than what we might like it to be. The idea of about 1/2 pound a day comes to mind. A lot of times, it will be water that we'll lose. We don't tend to think of water being a significant part of our food but it typically is, plus, it's not too uncommon for fasting to see people drinking less.
So don't beat yourself up too badly if it seems like most of the weight seems to wanna come back right away.
I actually haven't done a long term fast for a good while. About the closest I usually get is OMAD if I decide I'm not hungry for breakfast.
I also find that I get my most significant moves on the scale when I spend a lot of time with the push mower. Granted, lots of sweating and water weight involved, but... I find that when my body sees a lower number for a day or two and doesn't die, it somehow seems to get the idea that it's OK to be there. It's easy enough to put it all back but repeating the push mower thing in short order seems to help me to slowly ratchet down the weight in such a way that my body doesn't rebel. But that's just me. Others might not have the same experience.
For the past few years, I've tended to put on a bit of weight over the winter and take off a bit of weight over the summer. I don't get too excited about it and it's probably a 10 to 12 pound range. That's a lot for some people, not enough that I really notice anything significant, don't need new clothes or anything, just a matter of them fitting a little looser or tighter depending on the season.