Very worried about my staffy Questions

Hello...

I have just joined as I am very worried about my staffy
My girl is almost 7 (August) and approximately 6 weeks ago developed a bloat to her abdo area (ascites), vomiting and diarrhoea.
Went to vets immediately and they did x ray and ultra sound scan and found no abnormalities. She has a low protein and b12 - receiving 4 weekly injections for this - last one this coming Thursday.
Went on antibiotics and then steroids - stools became more formed and bloat went down.
However, a few days ago the bloat returned and her stools are looser again.
She’s eating and drinking and acting her normal self but this fluid is really really worrying me. My husband wants us to try another vets but I am reluctant as I don’t want her to have same investigations unnecessarily again.
Please help...has anyone else’s staffy ever had this?
I’m so worried about her.