If you wake up every day feeling like you got hit by a train and also have anxiety, depression, chronic heartburn, or exhaustion (not sleepiness, like a wired but tired) I would highly recommend looking into Upper Airway Respiratory Syndrome (UARS).

UARS was coined by Dr. Christian Guilleminault who was on the team that coined sleep apnea. Over his career he slowly widened his definition of sleep disordered breathing from choking (sleep apnea) to any nasal resistance that causes wake ups.

You be young and perfectly healthy but due to bad anatomy have micro arousals throughout the night. Becuase your young, your body fights through it (cuasing exhuastion) and will wake up up to readjust your airway. You won't remeber any of the wakeups, but many suffer from insomnia from it. The two big issues is large tongue in underdeveloped jaw that falls back and constricts your airway (you can test this with a mallamapati test) or a small nasal passage way.