Bizarre Voice Problem?

This may not be as bizarre as I think, but it's very strange to me. Now recently I haven't been getting enough rest and haven't been drinking enough water and oversinging, so I KNOW that's a main cause but...whenever I sing anything past a high E, there is another note created exactly an octave down without my willing it to. It isn't Tuvan Throat Singing, I feel a distinct buzz that also creates a note that is an octave below. If I rest it naturally goes away, but I rested for 3 days and it came back. What do you guys think- Much longer waiting time, or see a doctor?