Mucus plug question

How do you know it's your mucus plug and not just discharge??? I was vacuuming and randomly felt wet down there. I stopped and checked (not urine or fluid) and found some thick white-clearish colored discharge. It was not in one clump like I imagined so not sure it is the plug or normal discharge. It was more of goo consistency not a ball of mucus or anything. Just weird how suddenly it came. Has anybody had this happen? I am due in 2 days!