Ended up with a headache pretty quickly after coming into work, probably from the stress of having customers coming into the store like 2 minutes before we opened. So it was a busy consistent day of helping customer after customer after customer. *exhales* 
And I just...stressed myself into a headache.
Tried to relax and take meds, but it persisted.
Got worse.
To the point where it was difficult to be upright without feeling nauseous.
So. Took a shower and more meds and hopefully sleep will get rid of it.