Before the amazing people at Fleet Feet took the time to go over my running stride and figured out what type of shoe (and size...) was best for me, I was apparently running with a smaller size shoe.
Today, I only have 9 toe-nails, and one of them is black. Not to worry, all ten usually make a comeback by November/December and they all look normal before changing colors again as the season kicks off. I'm hoping this won't happen with the new shoes since now I'm wearing the right size.
Although after I saw this picture today... seems like I'm not the only one with this problem. :)