UTI problems

So I have to set an alarm every two hours every night to wake me up and go pee because if not I wake up with a HORRIBLE UTI.. 😭 and I have talked to my doctor every time they say just drink more water but I already drink more than 15 glasses a day. And if I drink more I’d explode. And I even changed to all cotton and no dye panties and still I get them. I am 22 weeks pregnant and the only think to ensure that I’m not in pain is at night pee every two hours and take cranberry pills every night.