I Have Been Feeling Nauseous, Sometimes Dizzy (feels Like Vertigo)

I have been feeling nauseous, sometimes dizzy (feels like vertigo) for the past few days now. I am diabetic and on NPH insulin and metformin. For the past 3 weeks I haven't been religiously taking my meds so when I start with Metformin again, I get the side effects of diarrhea. My last a1c was 9.5% it's probably higher now. Could my nausea be a cause of metformin or insulin for that matter, having been off on meds recently?