Leaving for family vaca tomorrow morning at 5am. Should I take Imodium before we go?? HELP!!

I'm leaving for vacation tomorrow at 5am. I usually wake up 2 hours before car travel to make sure I can use the bathroom enough. My question is, should I go ahead & take the Imodium before we leave? I usually do, so I don't have to crap in any rest stop bathrooms. I HATE the toilet paper situation in rest stops! We will be in the car for 6 hours, depending on traffic. I also have some Metamucil. I didn't drink any last night, nor will I drink any tonight. I don't really know what to do tho. Bc I didn't go yet today & usually I drink the Metamucil at around dinner time & then go by noon the next day. But since I didn't drink it last night, I haven't gone yet today. REALLY don't wanna have a tummy ache tomorrow morning! Any advice on what I should do??