Remember that where you are in your menstrual cycle will show up as water weight gain, so even though you ARE losing weight over all, during the week before your period it may look like you gained 2 or 3 pounds. If you normally gain 5 pounds of water weight before your period, then that means you have actually lost 2 or 3 pounds that week, even though the scale registers a gain. A better indication of how you're doing is how your clothing fit on your body. Are your favorite clothes fitting a bit looser now?
PS when I added some psyllium and Bentonite shakes during the end of my Master-Cleanse fast, the Bentonite absorbed a lot of water and constipated me, causing the scale to go up a few pounds. When I cut back on the Bentonite and drank more water, the scale went back down.