I had some problems w/ this when I first started Lexapro, 5mg. I had nausea and diarrhea for about 2-3 days, then it passed as my body adjusted to the new med. When I increased to 10mg, I had a little bit of it again, but it passed quickly. When I increased to both 15mg and 20mg, I didn't have any of that at all.
I think it's normal, and just your body adjusting. It's annoying and gross, but it should pass. Give it a few more days. If the Lexapro ends up working for you, it'll all be worth it in the long run. Good luck!