insomnia
"I have been taking Ambien for 12 yrs now.  I took my 1st Belsomra 3 hours ago and am still wide awake and the only thing I have felt is extreme nausea.  I never get nauseated from medications.  In fairness to Belsomra, me taking Ambien for so long may have made me too tolerant.  I will tell you that my doctor also gave me Zanaflex, which I took last night.  After 2 days of NO sleep, I fell asleep within 10 minutes.  Once it hits you, you kind of lose control of your ability to walk or speak without sounding drunk.  My husband had to carry me to bed.  It's apparently a very potent muscle relaxer.  It works.  However, I woke up 3 hrs later.  That's typical for me on any sleep meds though.  Ask about Zanaflex if none of the others work."