Feeling a tad discouraged

I am having a nervous moment. I hopped on the scale this morning and it showed that I hadn't lost any weight. What the heck? I have been staying within my points, drinking a ton of water and I have been going walking at the mall in the evenings with my friend. We figure we have been walking about 3-4 miles a night. We have gone 5 out of the last 8 nights (we took the weekend off). The only thing that I can see causing issues is that it is that glorious time of the month for me. Oh well, I hope by Thursday night I will be down at least 2 lbs, if not more.