What's up with the discharge is it my mucus plug?

I am now 36 weeks and 4 days pregnant. I went to my OBGYN for an appointment last week and found out I was dialated to 1 woo hoo lol. Anyway when I got home that night I noticed what looked like old blood in my underwear,and since this time I have been leaking a mucusy like subtance - which seems to come and go. My question is , am I loosing my mucus plug or is this just due to the cervical check?