Stupid teeth

A few days ago I woke up with an odd feeling in my teeth, like I had slept with shims in between them. Slowly over the next few days one tooth started to be very sensitive to cold and even the act of air passing over it. Anyway long story short I went in to the dentist today and the good news is it's not a cavity. The bad news is it could be worse. It's either a dying tooth (dentist doesn't think this is it and let's hope not) or perhaps the way I grind my teeth at night is affecting it. Either way it will probably cost about 500 bucks minimum to solve the problem (night guard or root canal).
Anyway here is the sock progress for yesterday's knitting: