If you did yoga and pilates after the knee drainage especially if you were engaging your knees in any way, such as in warrior poses etc and especially doing step & lower body weight work you may definitely have done too much too soon. What did your doctor advise you to do post drainage? You may want to go back to your doctor with your concerns and what you did. Definitely rest your knees for now and ice and take some anti-inflammatories like Advil. Try going back to your doctor with your concerns. And when you knee has no swelling and the pain has died down go back to activity slowly. I know it's frustrating as I have knee issues too and I hate being slowed down by them. I spread out my workouts with step one day and weights the next always allowing my knees a day off between knee engaging workouts and I always wear my knee braces to work out even if it's just upper body weights, and I always ice afterwards. And if I wasn't so sensitive to meds I'd probably even take an Advil after or even before any step workouts. I hope this helps.
