yep yep! periods can definitely play a bad trick on your scale. Don't worry about it too much. I usually don't pay attention to the scale around that time of the month because I know I'm probably bloated and holding on to a few extra pounds. It sometimes goes up a bit, other months, I just stay the same but it won't show any weight loss until after my period.
Plus, remember that some weeks, you're body might not lose just because it's being stubborn and holding on to those dear pounds for a little while longer, but keep up your good work and you will win eventually
Don't let that silly scale throw you off course. Wait a bit and if it still won't budge, than talk to your meeting leader and maybe go over your food/activity log to see if there's anything she can suggest
But if you're like me, you're just retaining water right now and your weight will soon go down.