So, DrugCrazed, are you DOING anything about having 'The Holly and the Ivy' stuck in your head? Such as:

Go to a pharmacy. Take some Claretin or equivalent. See if allergies are a factor.

Pick up an instrument. Play the song. Modify it. See what happens.

Think about your environment. Do you have a co-worker named Holly? Is there ivy climbing up a tree near you, and do you notice it every day? You can talk to your brain, you know. You can say, "Stop that. Holly is the person at the next desk and has nothing to do with a song."

If it's really bad, keep notes on how many times a day it bothers you. Then see a shrink.