Good Evening Dr. My Question Is This. When I Am

Good evening Dr. My question is this. when I am sitting for long periods of time, my right ankle swells up and when I go to sleep at night, it is back to normal size in the AM. I Do also have MS which under a Neurologist care and 2 medications associated with the disease, as well as TOVIAZ a bladder control med.
I do not have high blood pressure and do not smoke or drink, but yest I am overweight. I do have to say that I do not drink hardly any water because the peeing issue is a problem and I do also take severl vitamins. any thoughts or suggestions?