Can you become 'stupid' from a head injury?

[lglag]

I recently had a terrible head rush after being dehydrated and fell and hit my head on a concrete floor. I tend to be able to absorb and use information rather quickly, is it possible to lose this skill after that kind of accident?
This happened only minutes ago and I have stopped feeling any sort of pain, but I also haven't tried "learning" anything. My balance is a little off, but it seems to only be from nervousness or being startled by the whole situation.