Positive fFn and preterm labor

I posted yesterday about this but I have another question. One week ago, I was 23 weeks 2 days, and went into preterm labor and was eventually given Brethine. Yesterday, I had a fFn test come back as a sure positive and was started on the steroid shots and Procardia every 6 hours for the next 12 weeks till I am 36 weeks. I am not dilating but still having occasional contractions. My question is this, if you had a positive fFn test, how long before you delivered and what is your experience with it And what was your instructions from your doctor or midwife.