Metformin!!!!!

Bhawna
Hi frnz is there anyone who used metformin 500mg ER while ttc and got +. I am on it since 7 months. No bfp yet. No pcos. Well i was olwz regular with my cycle of 26days. But after metformin it changes to 27-28days and this time 29days. I am using opks and bbt to confirm ovulation also. Anyone??