Its well known in the MH world that a minimum of 8 hours sleep is crutial to a good working mind.
Some 20 years ago I was a shift worker of the most appauling hours. 12 hour shifts 12to12, afternoons (not so bad) and midnight to noon...crippling!
Why couldnt I handle not staying awake like the others? In security it was important to be on your guard.
Eventually I had a sleep study ordered by my GP. This involved attending a hospital in Melbourne overnight. Several monitoring buttons were attached to my upper body to record blood pressure and breathing, heart rate etc.
This report is sent to your GP.
In my case I had mild to moderate sleep apnea which meant I stopped breathing several times every hour starving the mind of oxygen.
I purchased a CPAP machine. We got a 12 volt one for camping reasons with a 240 volt power unit for when home. Essentially a cpap is an air pump that forces air regularly into your lungs stopping you from ceasing to breath.
Cpaps have a humidifier, a small tray you can fill with water if your throat gets sore. I have had no need to use it. Like anything consult your doctor.
Cpaps are known to increase your life span. They make you feel more alert during the day and no doubt help your mental health.
There are various masks you can purchase. The mask doesnt bother me at all now.
Eliminating poor sleep is one less challenge we have to bare towards the best outcome of our mental illness. If you are told you stop breathing while asleep or you feel sleepy in the afternoons, you might be best to attend your GP.