Sir, I Am Diabetic For The Past Three Years, But

Sir, I am diabetic for the past three years, but I am on medication Glycomet 500 2 times for the past 2 months only. Recently at a restaurant in Ambattur Immediately after having my Dinner, I fainted all fell and had mild fit type vibrations. I don't know whether it is because of Low Sugar level. My question is whether I have to consult a cardiologist and under some vital tests. Whether the above symptoms has to do anything with cardio system? Pl. advise sir.