Dear Annie: I am a 65-year-old woman who suffers from insomnia. I exercise regularly, limit my caffeine intake and try to wind down at the end of the day with more relaxing books or TV shows. However, there are still a couple of nights a week when I simply cannot fall asleep. I’m retired, so I don’t have to worry about going to work in the morning, but it’s still very frustrating to lie awake…