Does he hold up his leg in the air when he's sitting up? If he's still running around and isn't whining, it's probably not broken so hopefully xrays won't be absolutely necessary, but they might want to take xrays just in case there's a fracture or something. A yorkie's bone structure is so delicate that they can get fractures from just jumping around the wrong way. I would probably take him in tomorrow morning if you can afford to take the time off from work... is there anyone that can take him in for you - say a relative or close friend?
Keep up posted on what you decide to do and if he's okay - good luck!
Sending you lots of hugs and smooches from Frodo
