Spinning tonight, easy night

Lifted last night, squat, bench, deadlift and back extensions. While squatting my right knee did this weird crunchy thing and I think that messed up the night. Squat 75lbs failed, 70 lbs also failed, crappy squat night. Bench 65x5x3 so okay, deadlift 1x5x135, backed off on the weight. Four sets of back extensions starting with bodyweight, next set with the 5 lb plate, next w. the ten, next w a 15 lb dumbbell so those were okay. I behaved and went to bed with no wine but woke up sore and stiff feeling. So the plan is, Spin tonight and tomorrow am, lift tomorrow pm, spin thursday am.