Here is a website another member on YT gave me when my Tibbe was being worked up for possible liver shunt and I was told that the Dr. Tobias who writes the article is a leading expert in the field of diagnosing and caring for dogs with liver shunt and MVD.
Portosystemic Shunts FAQ
My own Tibbe was finally diagnosed with probable MVD after a couple of years of minimal symptoms which gradually got worse, leading to a high bile acids test, which called for a scintigraphy/abdominal sonogram and he's done well with just eating a hepatic diet for the past year. Since his symptoms were not that bad, the nuclear radiologists who performed his scintigraphy and sonogram decided he didn't really need to undergo a surgical biopsy for confirmation of the MVD and that just changing his diet would likely fix him up. It did. He's only had 6 or 7 bouts of spitting up bile and foam since that time, while his avoidance of eating, lethargy and head-rubbing have stopped and he's back to his feisty, playful, inquisitive self. He's allergic to the Hill's I/D Hepatic canned food so I feed him half that and half Hill's I/D GI kibble to keep his itching to a minimum but just that much of a diet change made a huge difference in his life. You baby could have the lesser liver disease of MVD and maybe won't need surgery but only a change of diet. They told me that dogs with MVD can live as normal dogs once they are on their special diet and restricted from other foods and can live out a normal small-dog's life expectancy.
I'll sure be praying that your baby doesn't have liver shunt but maybe is just dealing with MVD. Try not to be so scared - there have been several dogs on this website who have done very well after the shunt surgery when it was diagnosed early on after symptom or diet change for those with MVD.