I am on my third pack of this birth control and so its been about 2 1/2 months so far..my breasts are sore and tender and i am extremely skinny and ive noticed ive gained a little water weight like i normally do on my periods. I had my period last week and so its been about 5 days since it ended... is this remaining water weight from my period or is this from the birth control? I read where some women have gained a little weight on this pill and some who havent... what am i experiancing?