So i just got back from mexico and had what i believe was Montesuma's revenge. (diareah) Two days later i had unprotected sex and used the morning after pill about 4 hours after we did. He did not ejaculate but i know pre cum can hold sperm. I was wondering if now 5 days after getting Montesuma's revenge if that is my problem still or if is a side effect of the plan b pill. 
I need to know because my mom is urging me to go to the doctor but she does not know about me taking the pill.
Also, should i be telling my doctor i took it or does it not matter?