What the hell happened?
Stick with me, here. How did the weather change from the night before? Two of my guitars have the finish stripped off, making them extremely sensitive to humidity changes. The tone goes from lifeless one day to godlike the next. Humidity can also affect any component of the system and especially the air between the speaker and your ears. I've noticed that the best tone occurs around 45-50% RH, but we got a foot of snow yesterday in New Haven. The RH is now 24%, and it's not even worth playing. I suggest getting a cheap digital humidity gauge and keeping track. I got one at WalMart that also tracks the high and low for the day. You can then use a humidifier to help make the tone more consistent.