Mucus plug/bloody show and labor

How soon did you go into labor after losing your mucus plug/bloody show? I've lost small pieces before but since I woke up early this morning I have had large large pieces coming out with brown blood and spotting and irregular contractions and lower back pain and heavy pressure. Went to my drs and I was still 3cm 90% effaced where I was the other day when I got a sweep. Any experience will help