Hi Daniellec
It could have been a hind water leak. This is a small hole high up in your amniotic sack that is letting some of your waters leak. This is not a problem if it stops. (the hole often repairs its self). Your baby and your body will produce more amniotic fluid (your waters) throughout your pregnancy. The thick CM that you describe so well does sound like it is part of your MP. It is not unusual to start to loose your MP a few weeks before you go into labour.
I hope this answers your question.