Hypnagogic (or hypnogogic) adj relating to the drowsiness preceding sleep.
Hypnopompic adj relating to the semi-consciousness preceding waking.
Know the feelings? I do. The hypnagogic one is the one where that falling thing happens. You know that one? When you're almost asleep and in your semi-dreams you fall somehow and are suddenly jolted awake with a great fright! Not nice.