I fast a lot at least once a month. The weight loss is always different. My last fast was anazing. I lost ten pounds in four days, fifth day I did not lose as much, when I broke my fast. So I don't believe it is too many fasts.
It is known that during a monthly period women's body holds on to water. But that effect remain three or four days after the period ends.
I would not worry about it too much. Like I said I have gone through many fasts, some did not a good weight loss and last one blew me off.
Did you change your diet recently? That may have caused this change.