Do I have to drink 32 oz of water for my pelvic ultrasound

5'2 f 107 lbs, I am getting a pelvic ultrasound tomorrow and I’m a little stressed out about the water intake

Last year at this time I had one for period issues, I drank the 32 oz (maybe a little more I’m not sure) and it was so painful and uncomfortable.. I had to pee 3 times in the wait room. During the exam it was so bad I asked if I could use the bathroom one more time and they let me. When I came back they said the imagine was more clear and it looked better

So my question is because of that, is it safe to drink less? Maybe just 1 water bottle (16oz) before the exam? I want it to turn out but last time it was just way too much water I don’t think I can do that again..tried to call and ask their opinion but it was just the receptionist who said they can’t really give out opinions on the matter.