I lost part of mine at 28 weeks. Doctor has been doing fibronect test every 2 weeks to make sure there aren't other signs of labor... so far so good.... sitting in doctors office for the next one. ... though I had some bleeding this am... so a little nervous about the outcome.
You can lose you mucus plug multiple times. It regenerates on its own. Don't worry about it unless you start bleeding or have any signs of preterm labor.