Weight gain/Swelling After Weaning?

My LO is 10 months old and I just started weaning a week ago-- for several weeks until that point, I had only been pumping once a day (and no nursing). Around the same time, I also went back on the regular Pill. In the past week I have noticed I have gained a few lbs. (despite amping up my diet/exercise and losing weight over the few months before) and seem to be swollen-- my rings are hard to get off and my boots that I wear every day are tight...