Sleep is not the same thing as rest.

Some people sleep 16+hrs per day and wake up exhausted.

I hardly ever sleep yet I'm almost never tired.

People can lie in bed for hours and relax and meditate, without sleeping, and still feel rested.

It seems as though you were fine staying awake until you realized the time, then the fear of having lost sleep exhausted you mentally and emotionally.

Now you're always worried, which can keep you up, and exhaust your mind and body.

The trick is to use your downtime in any way necessary to rejuvenate your body and mind. Some nights it might be sleep, some nights it could be staying up on PC helping others until 0730am 😛 but as long as you feel recovered, you shouldn't let yourself worry.