Is herbalife a medication or vitamin because i think i have acid reflux i have prevacid (lansoprazole) but i have been drinking herbalife?

Oh, my goodness: Herbalife is a multilevel marketing (mlm) company which makes all kinds of herbal supplements and vitamins as well as other personal care products. Its "distributors" sell them at a large profit. I don't know which product(s) you've been using, but these are not medications -- nor are they held to the same standards medications are before being offered to the public.