Hi, I agree with Sarita that you should call the vet for more detailed instructions. Also, critical care has some general instructions on the Oxbow website if you don’t have them or they’re not on the bag. (I thought it was printed on it.)
You know, if you are not satisfied with this vet’s diagnosis and follow up, or are not comfortable with the minimal instructions you were given, by all means get a second opinion. You may find another vet that works with rabbits in the yellow pages under Exotics vets.
Otherwise, just call, leave a message and ask for a call back. If you are anxious, try following the instructions given by your vet and don’t worry about other things unless your bunny gets worse, not better. Often the info. on the internet can be scary. I mean, do you really need to know rabbit anatomy, or would you rather put your bunny in the hands of someone who has studied it at great length and knows how to treat for problems of that anatomy? I think you can get reassurance from either your current vet or a new one.
Tummy trouble is very common, especially in younger bunnies. You are doing well by introducing foods slowly. Just keep plenty of fluids with the critical care, watch those poops and bunny’s behavior. It sounds like your bunny will be better quite soon if the diagnosis is correct. And you can always ask a vet to do another test, as Sarita suggested. Often they try the simplest first, to see if that treatment works, saving you worry and money. It’s possible that’s happening here.