Opk strips-help?

Vicki
Im now on cd3 and i took a clear blue digital opk due to my irregular cycles and PCOS 
​It came back low
​When i ejected it there was this faint blue line.  Can someone help me understand the timing of sex around the "surge." And if there is already a faint blue line, does that mean i am going to be fertile sooner this cycle? 
? so confused