Doing God's Will
Joking aside, it's very understandable that you have mixed feelings about this.
Traditional religions manifest their effects on us in many ways both obvious and subtle -- especially when we're indoctrinated into them from birth.
The decision about whether to keep the cross over your bed seems simple enough on the surface, right?
If you want it there, keep it there. If you don't, don't. And that is indeed all there is to that.
The real issue, of course, is that you're not sure what you want.
One way to test the waters is to go ahead and take it down. Put it somewhere safe. There's no need to destroy it. Just leave it safely tucked away for a week or two.
Then -- when/if the thought occurs to you -- ask yourself if you would rather put it back up.
At that point, you'll know what you want to do.
If you expect humanity to disappoint you, you'll never be disappointed.