When I Whistle, I Hear an Accompanying Note

I'm fond of whistling, and today when I started whistling a tune, I heard a note in my right ear. I already have tinnitus in that ear (since about 3 years ago). I thought it was just a freaky one off thing, but it kept happening.

It's always the same note. When I whistle within a certain note range, I hear it. When I whistle outside of the range, it's normal. What the hell is this?

I should mention that I have some dental problems and in the last week or so I've had a toothache.