Nope -- you will be fine. According to the manufacturers, you probably have to quadruple the amount of yeast before you start seeing the effects of over-pitching. There are exceptions, however -- particularly any beer that relies on a characteristic yeast flavour, such as a hefeweizen, witbier, some English ales or Belgians, etc. Typically for these types of beers, esters and phenolics contribute predominantly to the yeast flavour, and if you really overpitch you put your beer at risk of being 'too clean' for the style. Even then, I bet it is hard to do.