It Happens When I Drive . Out Of No Where

It happens when I drive . Out of no where I all of a sudden get real tired,to the point of almost closing my eyes as if I cannot control it. It doesn't always happen, but enough to scare me...it will last about ten to twenty minutes . Then I will be fine. I am a type 2 diabetic..on meds. I also have petimal seizures...on meds for that to...