Feeling Discouraged

Couple things come to mind, one is that as was said it's mandatory to have 10 hours off duty. If your boss is asking you to violate hos , that's a serious issue.

The other issue is accepting to work around your natural body clock or circadian rhythm. I have severe delayed sleep phase syndrome. Have since I was a kid. In non technical terms, it's called being a night owl. While I can treat it for a month or two at a time with lighting, programming and other items, eventually I will return to my natural waking and sleeping times ( most awake from noon to about 5 or 6 am) I choose a job that fits that schedule best and most of the time I drive nights or swing. It is what it is. You may be an early riser, most people fall within a more conventional wakefulness area.

If you are continually forcing yourself to try to sleep when your body clock is telling ypu you to be awake, problems will occur. I had to take a hard look at accepting my body clock and adjusting to it. Some people's bodies are more accepting of varying their sleep cycles than others. What works for one person might not for others. Rather than risking medication, you might want to look at what your body is telling you.