Help Nausea and headaches

Went to the doctors, about a nausea and vomitting bug that I think I had on 29th of July, which hasn’t let up. Am still EXTREMELY nauseous, and have over the past week started getting very sore headaches (go down my neck as well)

My main complaint is the nausea Its absolutely debilitating I’ve tried peppermint oil tablets, Vicks nasal sticks, Cyclizine, gavisocon (tablets and liquid), Rennes, peptac, absolutely nothing works.

I’ve now been put on ondanestron, but if anything I think that’s made it worse. I’m now getting upset crampy stomachs and having diarrhea once ish a day The old stomach pain here and there which is only like a one out of ten

I’m at a loss

Has anyone ever found anything that’s really affective for nausea? It’s starting to affect my quality of life.