Thank you all for your thoughts - it's very comforting!!
She is now being tested for Addisons Disease- one of the Specialist at the clinic has seen one other Yorkie with similar symptoms and she had tested positive for Addison's.
I now wait to see how the test comes back from the lab.
She tends to look for things outside and around the house. I watch her as much as I can but sometimes she is so sneaky she gets by me and picks up or licks something from the ground. Yes, she is always fascinated by bird poop on the sidewalk or grass...starts rolling it it, sniffs it. I pull her away from it however it wouldn't be a stretch to say that she ate/licked some remainings of some poop outside. Unfortunately, nothing came back in her fecal exam
So back to square one! Pretty frustrating!
I will keep everyone updated. Going to see her now. Thank you all again.