Weight gain during period?

I've recently started to lose weight. I hadn't had my period in a few months due to being on birth control (I'm completely off it now). I started tracking my weight at the end of August. Yesterday my period started. The day before my period I weighed nearly 7 pounds less than I do today. I guess I'm just wondering if anyone else has problems with gaining lost weight back while on their period and if it will go away again once my period is over.