The building blocks were probably triggered last night when I had difficulties falling asleep after being woken back up. 
It probably was added to when I was dealing with the stressors also triggered last night and my helpless feeling where I don't know if I can do anything to help out certain situations.

But I'm pretty certain that the headache behind my left eye was triggered after having a group of like...six to eight kids (I have no idea how many there actually were but there was a lot of them) all under the age of ten running rampant around the store for at least an hour it felt like.
And like...while energetic and excited they were well behaved....at first.
But the longer the parent spent in the store with them, the less behaved they got.
Especially when they all discovered the dog toys made noise.
And began squeaking them nonstop for like a good fifteen minutes straight.

And noises like that can easily get on my nerves if they continue for too long. 

And their energy just got like...more chaotic. They got louder. 
And yah, pretty sure having to deal with the kids in the store is what triggered the headache.

Thankfully some rest and food and Advil seems to have helped it go away.
But we'll see if it actually stays gone.