I lost my mucus plug

Ta
What dors this mean? I have been having a lot of pelvic pain and pressure in my vagina all day. Then I just went to restroom and when I wiped I saw I lost my mucus plug. I'm a first time mom so I'm not sure what is next. I tried to call my doctor but they are already closed. I don't want to call the answering service cause it says to only call them for the oncall doctor for emergencies.