How many coffees per day do you drink? And what is the time of your last coffee? The half life of caffeine is 8 hours, and can inhibit deep sleep even if you achieve unconsciousness.
Actually, it varies. Two genetic tests an experience confirmed I have much slower caffeine metabolism. So no coffee after 11 for me, and ideally not a lot.
I just fact checked myself and found that the half-life is actually 3-5 hours. Sorry about that. But in any case, it's common for people to go to bed at night with some active caffeine in their system.