The last two nights have been pretty awful for me. I take my ambien at about 11:00 - 11:30. On Monday night/ Tuesday morning, I woke up at 2:00, 4:00, 6:00, and finally at 7:30. Tuesday night/ this morning, I only woke up at 4:30, 6:00, and then 8:30, but when I woke up that first time, I was up for nearly half an hour trying to fall back to sleep.
The whole point of ambien is that I'll fall asleep quickly and stay asleep all night. It worked fantastically the first two weeks. The last two nights, only one half of the equation has been completed. Which, as we all learned from middle school algebra, makes babies cry.
So, after two weeks of knowing what it feels like to be rested, I'm back to my normal pattern. Which makes my head hurt.