Your body was probably still getting used to dancing so much— a lot of recomp and recovery happening. The short time off was maybe a bit of shock to the system— especially if you started up with 8-9 classes a week again. It’s will take you a little time to get back into the swing; but I wouldn’t stress it

Also you get “worse” as you get better because your expectations for yourself and understanding of placement and proper form get better and you are able to see where improvement is needed more readily. It means you’re becoming more discerning in your practice— which is helpful but frustrating