I Am 60 Yrs Old And Recently OCCASIONALLY Find Myself

I am 60 yrs old and recently OCCASIONALLY find myself swerving all over my lane on the road. This isn't every time to be clear and NO MEDICATIONS OR ALCOHOL, even in the last several days are involved. Normally, I drive just fine. The one thing I've noticed is that my eyelids want to close and right before I seem to become totally zoned into the vehicle in front of me, kind of hypnotized if you will. Please help!