fFn test. Dilation. Loss of plug. 31 weeks

I am 31 weeks tomorrow ! I’ve been getting weekly progesterone shots and over The Weekend lost my plug had some bloody show and inconsistent contraction. Today I saw my doctor and he confirmed I did dilate to a 2 and my plug was gone . He did a fFn test which came back positive. I’ve been monitoring contractions in L&D for 2 hours now. I was givin a medication to calm the uterus but hasn’t worked yet .

Any other people can relate ? How accurate are the fFn tests ?