Always tired, but struggle to sleep

I feel like from the moment I wake up to the moment I get in bed I'm tired enough to fall asleep, but as soon as I need to it takes me at least 2 hours before I actually do. Is this due to being burnt out through the day, not actually tired, or due to overthinking and anxiety meaning my thoughts keep me awake in the night?

I guess my question is am I actually tired, or just burnt out too much to do tasks?