I agree with Sassy. There are SO many different kinds of BCP out there - it is not worth suffering through the side effects of one. Just talk to your doc and see if there is another one s/he recommends.
In the meantime, drink more water. More water will help combat the excess fluid. I hope you are drinking at least 1 gallon a day already. Also, eat less sodium. Watch the sodium in processed foods - it is hidden everywhere - even breads, diet soda, canned veggies, marinades, and salad dressings.
There are some foods that are natural diuretics .... asparagus, cucumbers, parsley. Eat more of these, they will help flush a little water out.