A sleep test might be in order. Ask your doctor.
I used to drive a lot as a musician. The coffee/cola jolt stopped working after a few years -I would "crash". What worked better for me is staying hydrated - lots of water - and food with few carbs. Protein or nuts as a snack.
Hope you get an answer soon!
"I have six locks on my door all in a row. When I go out, I lock every other one. I figure no matter how long somebody stands there picking the locks, they are always locking three." -- Elayne Boosler