Leela it may be a case of too much too soon. A weekend dance workshop sounds like a lot of time on your feet. Relaxin remains in the body for a period of time after birth, possibly up to 6 months. It relaxes the tendons including the tendons of the feet which means your feet and leg muscles have to work much harder to stabilize. This can result in joint pain. There is a article about that issue here
My Wife gave birth to our second child 6 weeks ago and started very gentle exercise at 4 weeks. She is now doing some light body weight work and stretching most days and short runs a few times per week. No issues so far. After her previous pregnancy she started back dancing after about 5 months. No issues initially but as she really got into it she experienced some back and hip issues. I believe part of the reason was technically she could perform at a certain level but her body had not recovered sufficiently to support that level of performance. She intends to take things slower this time.