Diarrhea post Vestibular

Okay, so, we need help with diarrhea now. Be warned, i do explain poop later in this post.

We're coming up on four weeks since our trip to the ER vet and diagnosis of vestibular disease. She didn't poop for about four days post vestibular episode, but when she did it was relatively normal all things considered. That lasted a couple of days, and then her poop started to turn into diarrhea - went from soft but formed to pudding like consistency to pure liquid that just came out like a squirt gun. It's sort of fluctuated between pudding like and liquid for the past week, with the occasional slimy residue thrown in just to make it more 'interesting'.

She has been on a bland diet of chicken and rice since the ER visit. She has picked at kibble but won't really eat it. We've been using chicken as treats to get her into bed and such. Sometimes she gets a bite of egg (plain). She isn't having accidents in the house (outside the normal pee accidents in her bed), she isn't rushing to go out and then exploding everywhere. Occasionally she has to walk around and "work" it out. She's eating and has an appetite as long as it isn't kibble (or anything too crunchy), but she has lost a little bit of weight (16.2 pounds at the ER vet, 15.9 pounds at her vet a week ago.)

Now, we have been to the vet about this. Twice. They've given us metronidazole and it helps, but it also plugs her right up. When we take her off of it, right back to diarrhea. They've also given us probiotics to see if that might help firm things up and regulate her digestive tract. It's been a week on those with no change. Best they tell us is "canine IBS" possibly brought on by a combo of the trauma of the vestibular episode, the vestibular itself, and maybe the antibiotics she was on for the UTI.

I'm not sure something else isn't going on, though. Or am i just being too impatient? There just hasn't been any improvement unless you count plugging her up with the metronidazole, and i would assume to see SOME sort of progress after two plus weeks. Anyone have any ideas? Is there anything i should be asking them to look for? I plan to call again on Monday, hopefully get her in, maybe run some blood and fecal tests. Beyond that i'm sort of at a loss. I would very much like to give her some sort of relief....