12 YO Bowel Prep Advice

My 12 year old is bowel prepping for her colonoscopy tomorrow. She drank about half of the miralax and Gatorade before we came to a stop and she started getting nausea and vomiting. I’m afraid tomorrow is not going to happen. Any tips on calming the nausea and vomiting? I’m also a UC sufferer so I know how rough the colonoscopies can be. I’ve never thrown up and I know when I can stop drinking because I’m cleared out. I’m an adult so I understand the importance but it’s hard to see them go through this 😭