Hi, Loperamide/Immodium is available over the counter in the UK so I should think that the side effects are pretty minimal for most people, although all
drugs can cause adverse effects in a minority of users.
If you google the side effects you can find them all on the internet, but that might make things worse if you are stressing about it.
If you are finding that the stool is too thick, maybe try half the dose am and pm, or just take one a day possibly after your main meal?
Another thing to look at is that you are actually drinking enough - although that sounds as it might make things worse, I find that generally the more I drink the better - one idea that was given to me was to drink water with a slice of lemon or lime as that helps the body to absorb more of the water rather than just excreting it.
Good luck with it, am sure others will have some more experience ....