I am going for a pelvic and vaginal ultrasound cause I have blood in the urine for qite some time with a negative culture and doc said something about appearance of white blood cells. I am going for test at 9 am today. was told to drink 1 litre of water and finish by 8am. I just woke with full bladder. do I hold it and then drink or can I go pee then drink? Plus I take two water pills everyday regularly and do I take that too? Last time my bladder wasn't full enough and I dranks more than a litre so I want to try to hold it? Should i and can I drinking another litre of water?