I've been on metformin for 2 mo i have pcos & i've been having diarrhea, severe stomach pain nausea & vomiting the last few days. could this be the met?

Yes: These are common side effects of metformin. Besides making sure you are not pregnant, you need to see your doctor about adjusting the dose or changing your medications.

Perhaps: This sounds more like a viral gastroenteritis, but since metformin can produce some of these symptoms as side-effects would definitely recommend you see your doctor and discuss this with them if your symptoms do not abate quickly.