Water pills

Can you still donate if you are on a prescription water pill. I just came back from a cruise and halfway through the cruise my ankles, lower leg and feet started swelling. I went to the doctor on Tuesday morning and I have already lost 6 pounds of fluid. I weigh 148 pounds and this is not happened to me before. I called my doctor to see if I can get off the pills because the swelling is gone, but I’m waiting for an answer. My question is how many days before donation should I stop taking the water pill … has anyone gone through this before? They deny you if you are on a prescription water pill?