On bc reclipsen extended cycle, end of 3rd pack.i've gained a few pounds this week, could it be because i'm schedule to have a period next week (pms)?

Used past history: Use your experience with past menstrual cycles as a guide. If you usually notice a little water retention and other PMS symptoms right before your period starts then this might explain the weight gain. If not then track your cycles and weight over the next few months to see if you can establish a trend. You can share that with your obgyn for further evaluation