Opks and PCOS

I have a question and it's been driving me nuts. Please can anyone in the know shed a lil light on this. I have pcos -  was diagnosed when I was 16. I take 500mg metformin x3 a day. I took provera to start my period this month, followed by my first round of clomid (cd5 -9). I don't think I ovulate on my own, even thou I have tried opks and they have always been negative (I use the clear blue digital - so I have never seen a smiley face there before) Then this month, 4 days after my last clomid pill (cd13) I got a smiley face on the opk. I had lots of cm, and it was quite stretchy, but not as stretchy as I have seen. I also had twinges for the next week in my abdomen. Do you think this was a false postive? Anyone know anything about PCOS and digital opks?