Yeah, that's not normal. A doctor's visit is definitely a good idea. I've read that a very basic "test" for a concussion is to have someone tell you a color, an animal, a person's first name, and a "thing", and try to say them back 3-5 minutes later. If you can't, then absolutely get looked at by a doctor. Apparently, short term memory loss is a common indicator of a mild concussion.
No man, you mean to say that it was 8 guys with bats and nunchucks, and you were able to dispatch three of them before the rest overwhelmed you, like the cowards they are.