I Have Had 4 Episodes Of Hypersomnia..including Memory Loss. I

i have had 4 episodes of hypersomnia..including memory loss. i dont remember laying down and hours later i wake up and have no recolation of, even, laying down. my first episode was 4 days after i took the new drug belsomra. i am a pharm tech and know the contraindications. i stopped after four days after i lost 7 hours of the day. i remember nothing. that was in feb. i had one today, 3 since then. what could be wrong? its not alcohol or meds. any ideas?