I Have Had Dirreahea For Two Months. I Was On

i have had dirreahea for two months. i was on a cruise when it started i have been to a gastroentrologist and had several fecal tests no blood but elevated white cells i have been on a mostly BRAT diet and taking three essential oils, oregano,lemon, and digest zen i have low energy and two to four bowel movements daily only two solid ones in two months what do you suggest?