I took an oxycodone around 9 pm for neck pain from an injury. Thus, I did not take my 5 mg ambien time release at bedtime (10:30 pm). It's now nearly 2 am and, while I've slept some, and dreamed deep, I have awakened often and now, I haven't been able to get back to sleep. Can I cut a 5mg ambien in half and take it, or should I even take it at all?