thank you for the suggestions.

contrary to what oilman said, I'm not asking for a diagnosis. It's helpful to see the list of things that others have done to deal with this type of pain, or the different underlying causes, since that might become useful down the road in chasing the problem. If X doesn't work, I can ask a doctor/etc about Y.

Note that for some people, a simple change of equipment eradicated their knee pain.

The hardest part is the psychological toll this is taking on me. I was getting much stronger this season, and riding much more than ever before. Best shape of my life. I want nothing more than to go out and do vicious workouts and race, but I can't. It's become clear that if i want this to heal, i can't even "go easy." i have to stop. As a result i'm feeling frustrated, depressed, and soft like i'm losing fitness every second.

Injuries suck.
I'm going to go back to the doctor to see if there's any serious damage.
And i'm going to speak to my coach about my position & pedal stroke to see if i'm doing something to cause injury.
And i'm going tomorrow for a professional fit to see if changing something about my bike setup will prevent this from happening in the future.