Fortunately I am not taking any form of HT. However, after I was diagnosed with PCa in September 2006, I started to have sleep problems. Prior to that time, I usually went to sleep immediately without taking any medication. My doctor prescribed Ambien CR 12.5 mg for me. I cut the pills in half as they are very strong. The half dosage worked fine for me. After taking them for a year, Medicare would no longer approve them for me without trying some less expensive generic sleeping pills for 90 days. I immediately changed to the generic form of regular Ambien (Zolpidem Tartrate 10mg) and was very happy with it. Again, I only take one-half of a pill or 5mg and they work just fine for me. I hope eventually to eliminate any form of sleeping pills. Perhaps you should consider cutting back the doseage of the Ambien CR or change to the regular Ambien (including the generic). I think that the Ambien CR 12.5mg are very strong and can result in tiredness and other negative side effects the next day.
The other important thing for sleep are your habits before going to bed for the night. You need to take time to unwind and avoid activities that would stimulate you before bed (e.g., tv). Maybe some reading or soft soothing music. I also do a few deep breathing exercises after getting into bed (take a deep breath, hold it for 5 seconds and then release it). It really can relax your body.
Here is a website with some helpful sleep suggestions:
Best of luck