Hi there! I’m doing the challenge as well and I also happen to be a physical therapist. It sounds like some pelvic floor insufficiency, which often times happens after pregnancy, but can also happen in very active people. I recommend kegel exercises and you could also seek out a women’s health specialized physical therapist for long term rehab for it. As for the cardio aspects of the challenge, I’d do more low impact- you could prob substitute with 40 sec hard on the rower, air dyne, ski-erg, mountain climbers…just some ideas!!