I Was Prescribed Amoxicillin For Pre-treatment For A Root Canal.

I was prescribed Amoxicillin for pre-treatment for a root canal. I have an important class this weekend Sat & Sun and cannot afford to get diarrhea during class which apparently is fairly common. I'm supposed to be taking 500mg one capsule 4 x day until finished. Should I wait to start the medication until Monday just in case? My tooth hurts but I can take aspirin all weekend to alleviate that.