Game over for me as well - inflamation over the knee cap (bursitis) - reached 45% - riding in torrential rain at 2°C the first couple of days started it.
If it's what you are having - and you insist on riding - you need to start out with 20-30 minutes of low intensity high cadence sub 100 watts and get that shit warmed up - if you feel discomfort at the end of this warm up you should quit, take a couple of days off and retry the gentle warm-up.
Game over for me as well - inflamation over the knee cap (bursitis) - reached 45% - riding in torrential rain at 2°C the first couple of days started it.