I have severe pain in my anatomical snuff box. What shouldi do?

Scaphoid fracture. http://www.aafp.org/afp/2004/0901/p879.html.
Possible fracture. Pain in the anatomical snuffbox needs to be evaluated with an x-ray and a fracture needs to be ruled out. Wouldn't wait to get this done. See your doctor soon, get the x-ray as soon as able.
Pain in wrist. The cause of your pain is not clearly understood based on the information provided. It may be a wrist sprain if you know you did something to it. There are a few tendons that lie in that area that can be affected. See doc for diagnosis and treatment.
Depends... Multiple possibilities including issues with nerve, tendon, or bone (tenosynovitis, schaphoid fracture, etc.) see your doctor or hand specialist.