The fetal fibronectin test is not very accurate. Read about it here:
http://www.wdxcyber.com/npreg02.htm
In the mean time, try to figure out what is causing the premature labor. Are you dehydrated? Try drinking as close to a gallon of water a day as you can. Do you possibly have an infection? A yeast infection can be treated with an over the counter solution or my favorite is Yeast Arrest (can be bought at a health food store). Also, avoid sugar, eat lots of yogurt (low sugar kind) and take Lactobacillus Rhamnosus or Acidophillus. The thing about yeast is that it thrives on conditions also favorable for an overgrowth of Group B Strep. A GBS infection can also lead to preterm labor and erode the membrane to infect the baby.
If you think you might have a urinary tract infection, it can be treated with 3 days of Uva Ursi. Here's a web site that describes all the treatments:
http://www.umm.edu/altmed/ConsConditions/UrinaryTractInfe...
One more important thing is to make sure your diet contains at least 80 grams of protein per day. You really need to force yourself to eat even when you don't want to. Start out with a large breakfast and include a breakfast meat. Eating right includes whole wheat bread products, protein, dark green veggies, lots of water, your prenatal vitamin, etc. Dairy is not really needed, but you need to fill in the gaps with other calcium rich foods (broccoli, spinach, almonds, etc). Avoid foods that are highly processed, fast food, white sugar and white flour, artificial sweetners, soda, etc. You may want to also add Rainbow Light Good Morning Prenatals to your prenatal vitamin. You take them in the morning and avoid calcium that could bind with iron. Do more of the calcium in the evening and it will help you sleep.
You most likely can stop this process with the right plan of attack! Good luck!