find a pathology that tests for blastocystis, and Dientamoeba fragilis they are both parasites, the patholgy needs you to provide to you (a special preservative/fixative) that preserves your stool samples, so the parasites arent all dead and gone by the time they reach the pathology and go undetected
how do i know?
as the same happened to be doctor suspecting strongyloides, but eventually it ended up being blastocystis parasite.
trust me go and find a pathology lab that tests using the fixative for blasto/ dientameoba that is your first step.
as its very common and i picked it up in thailand. and it has done exactly what has happened to you to me.
now im trying to treat it and it is VERY VERY VERY hard to erradicte im still trying goodluck