Fetal Fibronectin Test.

Has anyone else ever had one? I am 29 weeks tomorrow and had to go to hospital last night having some pretty intense contractions and excruciating back pain. After they gave me something for the back pain they checked me and said my cervix is open but baby is still high then they did the test. Which came back positive which means this baby will be here early just like her brothers. They were able to get contractions under control and sent me home with orders to be in bed rest for 24 hours well I love my boss she called to check on me and gave me clearance to work from home the remainder of my pregnancy. But anyone else ever have this test and once you got a positive reading how long afterward did you have baby.