Medication question about diarrhea...

I am currently on the Z-Pack to rid myself of bronchitis and it says “may cause diarrhea.” I have had diarrhea for the last two days going twice a day.

So I picked up an over-the-counter medicine to help with the diarrhea problem. It says to ask a doctor before use if taking antibiotics.

I made the mistake of taking them already (only once, though). Does anybody know if there will be any real problems or if it should end up being alright?