Id go to my local feed store and get something suitable for horses, since their belly activity is closer to a bunnies, than a cat or dog belly.

Dear Pumpkin! Benebac is good for rabbits. If you can’t find that, you can use dog probiotics if it has enterococcus faecium, a bacteria that rabbits have lots of in their tums. The probiotic should preferably not have meat in it, but many will have meat flavor and can still be used. You don’t want clay in it (montmorillinite or bentonite) because that can cause a blockage.
I hope you get well soon!

I forgot about benebac… I have a small amount stashed away in case of belly emergencies. Luckily I haven’t needed it yet.