I have a bad nausea and vomitting issue, so my doctor prescribed me with diclectin. Sometimes when I feel like the nausea is quite bad, I'll take this diclectin at night and I find that not only does it keep my vomitting at bay, it also helps me sleep.
Anyway, I also find that it's easier to sleep also if you take a warm shower or drink hot drink before bed, then turn on air con to be very cold.