Holding pee tips

I️ go for an ultrasound to check out my ovaries and such tomorrow. They said I️ have to drink 28 oz of water an hour before I️ go and I️ can’t pee at all. I️ have a naturally small bladder and I’m so nervous I’m going to pee on myself or not be able to hold it. Plus I️m afraid I’ll be in the waiting room forever and have to hold it longer than an hour. Any tips on how to distract myself or help me not pee all over lol. Im dreading this and so nervous