Switched to a very firm pillow last night and today I feel re-concussed
 

I feel HORRID today. As bad as I did back in November when I sustained my most recent concussion. Possibly worse. I haven't felt this poor in months. All ov a sudden. Out of the blue. My head is throbbing and I cant even remember what I had for breakfast this morning

The pillow I swtiched to last night is very, very firm. Like almost solid upon contact, then it sinks inward. I'm really afraid that I came down onto it too hard in my sleep or something. Is this possible? Can you concuss yourself from a firm surface like this? It's a really heavy pillow. I can't believe I thought that was a good idea. I dont understand whats wrong with me today.

Most likely it was the change of angles & the firmness of the pillow that affected your neck muscles..
Sore, tight, strained or spasming muscles & perhaps trigger points in those muscles can create discomfort & symptoms..

Not possible to get concussed from laying on a pillow.

Neck and muscle probs as Jo Mar says, most definitely.

Certainly yeah the idea sounds a little ridiculous, even to me.

But idk, it's like a really hard pillow. I feel like if I bounced my head off of it, it wouldn't be very pleasant. I toss and turn a a lot when I sleep too

The position on your neck may have reduced vertebral blood flow while you slept. That can make the following day miserable.