Motherhood = Ruptured Muscles?

Motherhood is hard on all kinds of levels. It takes a toll on you physically and emotionally. What I didn't count on was how hard of an emotional toll it would take on me. It seems that at some point I ruptured my right quad muscle. I have no clue when exactly this happened. I'm not in any kind of pain (other than the pain I feel every time I look at the groove in my leg). Anyone have any experience with this?