A Cavity?

I have a weird sensation in the upper right part of my mouth that could be a cavity. The weirdest part is that it’s not sensitive to eating, or cold, but I can “feel it” in my mouth when I step heavily. Some sort of bone conduction effect, at any rate.

I figure the possibilities are:

1. An actual cavity. I hope it’s not, since I’ve only been drilled once for a “pre-cavity lesion” on one of my molars.
2. A gum issue. This is probably something that would heal quickly.
3. A totally psychosomatic sensation caused by my upcoming dentist appointment on Monday. This would be the easy way out.

At any rate, it will all be figured out after the dentist yells at me for bad flossing habits, or something. I just don’t like the waiting…