This link goes to a good page with everything you need to know!! And yes, it says you had an egg that wasn't so fresh. Did you check the pack date on the carton?
"Many eggs reach stores only a few days after the hen lays them. Egg cartons with the USDA grade shield on them, indicating they came from a USDA-inspected plant, must display the 'pack date' (the day that the eggs were washed, graded, and placed in the carton). The number is a three-digit code that represents the consecutive day of the year (the 'Julian Date') starting with January 1 as 001 and ending with December 31 as 365."