Last (recurring) five pounds

I feel like this site is used by a lot of people who have a significant amount of weight to lose, but not so many who are trying to lose a small amount of weight. I started actually caring about my weight and health when I was about 20 and over two years lost about 15 pounds. I was never really overweight but felt a lot better about myself when I was finally 115 versus 130. Over a two-week period when I was unable to do my usual workout routine and ate a bunch of crap food, I gained six pounds. I was at the higher end of my comfortable weight range (117) and planning on tracking my calories to lose the three excess and now I'm EIGHT more than I'd like to be. I know that doesn't seem like a lot but I have a small frame and don't gain weight in a flattering way - solely in my stomach. I'm not overweight but I sure look lumpy. Anyway, I've gone back to my regular workout routine and dieting in the same way I always did but without any results. It's been two months and I haven't lost a pound. Can someone tell me what on earth is going on? I'm so incredibly frustrated and losing motivation, which is causing my diet to backslide. Is my metabolism slowing down (very abruptly?) I'm on birth control but have been for about a year so that's not it, and I just started taking iron supplements for my anemia so if anything my energy levels should have improved. This is weird and upsetting, please help.