Rock I never took Imodium with ilestomy. It will get thicker soon, just be patient. You don't need the Imodium, just let it flow naturally and empty it when needed. My output at beginning was watery as well but started to get thicker as the days went along. It becomes really easy to switch out the bag, I did it in 5-7 minutes after a month of having it. I had some issues where I would pancake which means poops seeps through the side under the ring. I figured out later how to deal with, just be more vigilante and push the poop downwards if you have to. Other then that usually things go well. I miss my ileostomy sometimes, but it is what it is.
Also I use to take the bag off during shower, but I stopped like 4 months in and never looked bag. The bag air drys or you can pat it with a towel and use a blow dryer if you want. It makes things easier.