Not losing weight on a water fast

Hi! I'm on day seven of my first water fast. During the first four days of the fast I went from 60 kg (132 lbs) to 56 (123 lbs). I started my period three days ago and since then I have not lost weight. Do you think that this happend because of the period? In the last 7 days I have only consumed water, no tea, no suplements. Tomorrow morning I will end my fast with watermelon. I'm a little bit afraid that I will gain all the weight back, because I haven't lost the amount of weight I expected to lose in 7 days.