So so tired

I can't remember the last time I was this tired during the day. I'm absolutely exhausted. I've been having a hard time falling asleep and then this morning I was wide awake at 5am. I drank 2 cups of regular coffee (when I usually have only decaf) and I still thought I wasn't going to make it through the work day. It might be a testament to just how tired I am that I didn't care at all that admin changed the schedule for next week three times- all after I've already completed my lesson plans. I am just too tired to be stressed.