Ok-as a vet tech, I have a few questions, sorry if you answered them previously.
Did you veterinarian check a fecal sample? In house or send out to a lab? Metronidazole is an antibiotic but is also an anti-diarrheal, which means the stools should be improving, atleast somewhat. Also, take all kibble away from her. You are defeating the purpose of chicken/rice or oatmeal by allowing her access to other types of foods. The goal is to give her system a break and allow only easily digestible foods. I do agree with Cami, stop feeding her for 24 hours...PERIOD. Nothing. No treats, no food...water only. If she still vomits, no food OR water for 24 hours. If she is still vomiting after that-directly to the vet for an IV catheter and fluids and anti-nausea meds.
Back to the fecal: some parasites are not easy to pick up on routine in house screening. He should seen a sample out to a lab to identify exactly what you are dealing with so it can be treated with appropriate meds.
Leaking urine seems to fall in with a bladder infection, but you said that was cleared up? What did he prescribe for that? How long was she on the medication?
Thyro-tabs are actually levothyroxine....which is exactly what soloxine is. Generic yes, but it is the same medicine. I would not freak about that too much. I know a ton of pets who have done just fine with Thyro-tabs, the point is that they are balanced over time...and it mostly depends on how they metabolize as well. It is going to take a while to regulate it, so dont panic.
I hope she is doing better, I will keep checking for updates.
Autumn