Feeling goofy after an accident

I have only had a handful of noteworthy injuries in my life but every time I do injure myself I feel giddy. Nearly everything seems funny and I start babbling like an idiot to anyone who will listen. Why does this happen? I'm not talking about head injuries. This happens if I sprain an ankle or cut myself accidentally. I'm assuming its some sort of weird adrenaline response but I've never heard of anyone else having this problem.