I lost some of my plug three weeks before I went into labour and a bit more 3 days before going into labour.

Someone also said earlier that a long prelabour = a short labour. Not necessarily so. I was in pre-labour for 9 weeks (confirmed by Obstetrician) getting mild contractions every 12 minutes for 9 long weeks and my labour went for 23 hours!

Good luck and hope you see some plug soon!