I think this happens to everyone, and it’s normal. Personally, when I drift off, I try to shift my position and try very hard to sleep. However, that makes sleep become even more evasive. Try to relax and be present, not necessarily try to go to sleep. If the thoughts keep running around, focus on your breath. Notice where you feel it, notice its sound, and notice the rising and falling of the breath. After concentrating on that and nothing else, I find that the mind comes to a place of rest, and you’ll wake up sooner than you realize in the morning.