I'm a bit embarrassed to ask this really

but how do I know if I've lost my plug???! What exactly am I looking for and does everyone lose the plug before labour starts or can it happen at the same time??
TMI bit coming up... I've had a fair bit of discharge and there was a kind of gooey patch at one point and I wondered if that was it or part of it but I really don't know and don't want to ask my MW as it feels too gross to ask anyone about it face to face lol
Lxx