... Yesterday, would I have been able to put my skis back on after resting for 10-15 to ski down the rest of that run? Then get back on the lift and do another couple mile long Blue run (but the entire time on that Blue run being afraid my knee was going to buckle)?

I'm sure something is really wrong, and the pain is in the MCL area. X-rays showed nothing broken (not surprising). Visiting an orthopedic surgeon is the next step.