Why do I feel drowsy and tired for hours but can not fall asleep? I took only 1 acetaminophen codeine 300/60 around 12 am. I want to sleep but can't

Sleep apnea??? Hard to say. The meds might have built up a resistance to helping with sleep and may actually be inducing lack of sleep. I would consult dr. Asap and you may have to have a sleep study if this problem persists.