You either have narcolepsy and need to see a doctor, or a REALLY boring job,and need to find something more challenging.
Time to see the Doc and get a check up - this is NOT normal!
How do you sleep at night? Ever read about "sleep apnea"? May do you some good to read up on it. Maybe get checked out. Make sure you go to a good sleep disorder clinic and not a regular MD.
See your doctor, you may have sleep apnea which is resulting in you getting a good nights sleep.
coffee... works for me...
Hope you're not a lorry driver