Hello and thanks for using HCM.
I have read your question and understand your concerns.
In my opinion, it is most probably a
concussion that is causing your symptoms, because there was no
loss of consciousness and vomiting after
head trauma.
In addition, 8 hours passed, so, just
dizziness points toward concussion, not other more severe damage.
I think you should rest and take for example
Ibuprofen 400 mg to ease your symptoms.
In case you notice other symptoms such speech problems, nausea or vomiting, difficulty interacting with others, you should be evaluated further by your Doctor and probably by imaging studies such head CT scan.
Hope you found the answer helpful.
Take care.