I Am 30 Weeks Pregnant And I Have Had Constant

I am 30 weeks pregnant and I have had constant diarrhea for 2+ weeks now. I called my doctor on Monday and the nurse told me to take pepto which hasn't helped.. i started eating bananas, potatoes, breads, and drinking lots of water and OJ but I am still running to the bathroom multiple times a day. I am not having any contractions, but mild cramping and persistent diarrhea. Should I be concerned?