Why am I so slow in the mornings?

I have one morning shift that I loathe with the entirety of my being. I am more prone to making mistakes and experience a sort of brain fog that lasts 2-3 hours after waking.

I can't wake up as easily as I'd like; it takes me a good 15-20 minutes to find the will to move from the bed and even then I'm just forcing myself.

I'll admit that I tend to be more active at night. It currently being 1:03 a.m. while I'm typing this should be evidence enough.

Why is it that I can't think clearly in the morning even when I've been awake for 3 hours?