You can go ahead and hope for the best (which is what most folks do), you can shelve it out of fear, or you can try to figure out which song it sounds like, and change it enough so that it doesn't any more. Or you can find a melody that is out of copyright and fit your lyrics to that.

Anyway, if it is a potential hit (and I've just got to believe you when you say it is) then you owe it to the world to get it out there. Even if the court rules against you (which is actually rather rare), you'll get to keep some of the money, which is better than shoving it in a drawer and not getting anything.