Concussion symptoms sure can show after few days. It can show after months too. For me the disabling symptoms got worse - mainly terrible dizziness, panic attacks, pain, dull headaches all showed up after 5 weeks or so. For the first 5 weeks I was recovering good but not resting. So that may be the reason or I don't know. No one knows anyways.

Is dizziness is the only symptom for you? What medicine you are on? Be happy it is working since here some of us struggle with dizziness with not much help. There are so many types of dizziness by the way.

Best thing to do is take it easy and not push it for at least few months. You are way too early in your recovery.

Cheers!