It seems like as soon as a sperm fertilizes an egg they send a message straight to your nose. Suddenly you can smell EVERYTHING, from a coworker's perfume or (gag) the burnt sludge at the bottom of the office coffee pot. (Really, it's just the estrogen surge that heightens your sense of smell, not a secret pact between your embryo and your nose.)
Thankfully, this too shall pass—and sooner than you might think. That super sense of smell will most likely go away near the end of the first trimester.