Hi, Yesterday When I Was Swimming, I Went Underwater And

Hi, yesterday when I was swimming, I went underwater and hit the top left of my forehead on the bottom of the pool. I came up and continued on with my night. I didn't feel sick or confused or anything, I felt fine. Now today I have a very dull headache if any, and I can't quit yawning. I'm very paranoid that something has happened and I don't know if I should be concerned or not.