I don't believe my condition is that bad "yet".

It's a common enough phenomenon. Usually it manifests itself when one hears a snippet of a tune from someone else, often some trivial little pop tune or a TV show theme song. I had it once when Hanna of Hanna and Barbera died and the theme song from The Flintstones attempted to swallow my brain. Fortunately my main man, AnnaStrophic, gave me a gift of Quia Fecit from the J.S. Bach Magnificat in D; it has the power to exorcise any other piece of music.

We also suffer from this phenomenon for about a week after any one of our twice yearly concerts, but at least it's quality music running through our brains.