laxatives with emetophobia

so i have like very bad ibs-c and I’ve just went to the doctors todays and he’s prescribed me three laxatives miralax, magnesium citrate, and dulcolax, and he wants me to take and all and I’m nervous as fuck he said something about take the dulcolax at night before i go to bed, then taking the whole bottle of magnesium citrate once i wake up and 3 capsules full of miralax in gatorade i have no idea how this is gonna go but im literally terrified i have not gotten anywhere with my mental health so v* still scares the hell out of me and even feeling n* scares me so much whenever i have ibs flare up’s im traumatized after, but has anyone tried to do this im pretty sure this is like a cleanse for impacted stool but im really trying to force myself into doing it but I feel like once it comes time saturday night to start I’ll chicken out because I don’t wanna v* from it, obviously i want feel better because I’ve been in severe pains for awhile and my zofran has just completely stopped working and I’m not sure if my zofran would even work with stopping me from feeling n* from these laxatives, does anyone have any advice or has anyone after tried doing this and v* ?