The very first thing you do is to call your doctor and tell
him what is happening.
class of drugs belong to Erythromycin
The most common side effect is nausea,vomiting
Eventhough this does not happen in everyone,some are more
likely than others.
You may need a new class of drug.
It is possible that you may react ther same way if you take it again.
Please check with youry doctor.
Wish you well.