Help-8 year old w tummy troubles

Help! Daughter aged 8 has had tummy upset for about 6 weeks. Same symptoms passed through the other three members of family but daughter seems most effected and can’t kick it. Main symptoms were vomiting, gagging, belching and upset stomach. Vomiting subsided.

Had two Rounds of stool tests - negative for parasites/Ovu. Since I had similar symptoms I had stool test also- negative.

Before we all had symptoms pedi put her on Prevacid. After symptoms passed to us GI said wait. When symptoms didn’t go away for her did a round of flagyl when he suspected giardia even though both of her giardia tests were neg as was mine.

She Vomited undigested food after 9 hours so just did a solid and liquid gastric emptying study which was all normal. GI said post viral something and it will take time to get over it- but 6 weeks?!? Really?!?

I’ve seen this type of thing floating in her bath once before but thought it was a leaf or something. Now wondering if it could be related.

I Pressed for more stool tests or blood work and docs say parasites would result in not solid stool (hers is solid) and since it’s infectious (family members got it minus the vomiting- no need for blood work.

Have her on prevacid and probiotic currently. Just finished flagyl a few days ago.