I Drank First 2 Liters Of Gavilyte-n Solution For Colonoscopy

I drank first 2 liters of gavilyte-n solution for colonoscopy prep. for 7am procedure tomorrow. I am feeling nausea just thinking about trying to finish drinking the remaining 2liters. Additionally, I took 2 5mg bisacodyl pills. My stool is clear liquid now from first 1/2 Gavilyte. Do I have to drink remaining 1/2 solution, as I am feeling mentally sick just thinking about it.