I'm inclined to agree with
@Trabaho with this one, getting rocked in sparring or in a bout is more likely your bodies reaction to your neck being jolted by a punch causing your bodies nerve signals to get wacky for a few seconds i.e electrical impulses sent from your brain are interrupted and it takes a few seconds to resume normal programming. It's likely not a concussion. There are different severity of concussion however and minor concussions should be treated as any other concussion with adequate rest before sparring again.
If you feel "off" or "cloudy" after sparring you could potentially have a concussion.