Any advice on my recent numbers?

I’ve been fasting since December 27th. Initially, two days a week (Monday and Thursday). In the beginning of February, I started Monday, Wednesday, Friday fasting days. Typically I stop eating around 8 pm, fasting through the whole day, and eat again between 8 am and 12 pm the next. So usually 36-40 hour fasts. It has been going good - I see some zig and zags but it’s been trending down week over week. Within the last few days, it’s gone a little haywire. I haven’t changed anything about eating or exercise. I don’t know what the explanation is so I don’t know what I might need to do differently. Some details are below in case anyone can help me decipher what’s going on! I’m still following what’s been working, I’m just disappointed at this moment. 39f / 5’0” SW 204.0 lbs (Dec 27) CW 191.6 lbs Feb 22), loss of 12.4 lbs Lowest was on Feb 18: 185.1 lbs, loss of 18.9 lbs Recent weigh ins causing confusion: 2/18 185.1 lbs 2/19 188.6 lbs 2/20 191.6 lbs 2/21 190.5 lbs 2/22 191.6 lbs Eating: 2100-2500 on eating days. Calculated based on equivalence to 1200x7 or 1500x7 to keep my weekly total where I want it. No particular diet other than trying to make better choices. Activity: Walking at least 1.5 miles a day / 35-45 minutes of outdoor walking. Some days I also use our home elliptical but I have a 3 year old so it’s hard to get that free time some days. Finally, I don’t measure body fat percentage often because it doesn’t seem super accurate but my scale can do it. 2/6 45.2%, weight was 190.6 lbs 2/22 43.5%, weight was 191.6 So I’ve regained 6.5 lbs. Usually I go down maybe 3 lbs after a fasting day, back up 1-2 lbs, and so on. I’m so disappointed to be back in the 190s. According to the body fat percentage reading, I’ve lost lbs of fat, but what has it been replaced with? Surely that can’t be all muscle (with the sudden uptick) so it must be water.