Hi and WELCOME to YT. So sorry your kiddo is sick w/ IBD, that has to be just miserable to watch her go through
. There are other folks here whose yorkies have it, so hopefully they'll chime in.
Have you tried Tylosin yet? That works for some IBD dogs. Have you ever tried a homecooked fish diet for her? Have you put her on probiotics to repopulate her small intestine's flora?
When she was a puppy, did she happen to have Giardia or any other infection that affected the GI system? This would be very important to know.