I was diagnosed with severe obstructive sleep apnea. I started with CPAP in mid February. I don’t have trouble going to sleep. About 2 months into using CPAp , i started waking up in the midline of the night and being awake for hours. My sleep PA recommended intake low dose extended release Melatonin. I took 5 mg for a few nights. I felt groggy and really tired the days after taking it. I stopped taking it as it was making me too tired and groggy.