I had my entire colon removed with the small intestine connected to the rectum and had the persistent and frequent diarrhea that results.

Even half an Imodium would cause serious constipation and even 1/4 made things too tight. Interesting how different we can be!

What Mayo suggested was a thick slurry of Metamucil for tightening the diarrhea. It took a lot of experimentation to determine how much and how often. Note that this doesn't reduce the frequency of having to go. Activities such as drinking too many fluids or getting dehydrated still can upset that balance. I avoid drinks with sugar and HFCS because of their effects of a diarrhea and try to limit fried things. There are some places I can't eat because of the kind of cooking oils they use.

So what does that mean for you?
1) The metamucil trick previously noted is worth a try but without a rectum who knows?
2) It may be worthwhile to look at your diet for things that make things worse.

A question for others since I have no personal experience. Isn't this a bit unusual to remove the rectum without doing a bag?

Wish I had a good answer for you.