My vision fades while i drive and comes back a few seconds later...should i be worried?

everytime i drive i am very precautious and im a safe driver but sometimes my vision fades and i catch myself thinking on random things that sometimes dont even make sence...i cant control it, and no matter how much i try to concentrate and and focus on the road, my mind just goes to another place, its like my mind leaves my body, but my body keeps driving as if nothing is happening, i dont even realize it until after it happens, i've been on the verge of crashing but lucky i never have...i dont know what i can do about this is it a disorder or an illness?