Hi,
We are in a very similar situation! I am on day three of a (hopefully) 21 day fast, but after that I plan to do rolling 7 days until I hit my goal. My goal is 125. I am currently at 175 at 5’5” F.
I have done multiple fasts from 3-10 days. In all my other fasts I have lost weight quickly the first few days, but this time I have only lost a couple pounds so far. I have not been hydrating enough I don’t think. I usually drink a lot more water, and I read that taking sodium while not drinking enough water can make you retain it.
I think a reasonable expectation is averaging about a pound a day weight loss, and taking into consideration when you start eating normally again gaining back a few pounds. I am not as well versed in long term fasting, though. I know I have ranged from day to day losing nothing to about three pounds max. I think it depends on the person.
Happy to be your fasting friend along the way!