Advice needed for tomorrow

Hey everyone, i have a funeral tomorrow. The funeral is almost 2 hours away by car, very crowded, in a heatwave, with fighting family members also the final resting place is pretty far away and literally all of those things can make me flare up. My endometriosis is against and in my gut and touching my bladder so i already cant wear the nice jumpsuit i got since i would need someone to zip the dress when i need to get in or out of it. The other options i had is a way too big top and i feel like a trashbag in it but its safe and accessible so it will have to do. Im trying to find ways to survive this funeral. I'm absolutely terrified for the pain and endo shits during the funeral and the stress from that isn't helping either.

Does anybody have any tips for me? In about 12 hours i need to leave my house for the funeral.