Aiyoh mummy, this one really need to check with your doctor or go to the clinic asap, okay? Better safe than sorry when it comes to pregnancy, any leakage or discharge yang berlainan from normal should get checked out properly, especially at 21 weeks. A few of us mum friends had similar worries during pregnancy and the doctors put our minds at ease once we got checked. Jangan worry too much lah, but do see someone soon just to be sure everything is okay with baby and you. Sending you lots of gentle thoughts!