I have a 13 week old yorkie pup(what the misinformed may refer to as a "teacup"
) and believe me I wish he were a little bigger. At 12 weeks he was a little over a pound(completely healthy but extremely tiny). I basically have to treat him like a premature baby at times. I have to be extra careful with him more so than ppl with 5lb + yorkies. Your little boy is adorable btw