You ladies on metformin?

You ladies on metformin, how long did it take to ovulate, month wise? I've been using opks since I started the meds and I've been on it since the 13th, no spotting, no change in cm, still some mild cramping in my ovaries but not extreme. Just haven't seen a positive opk ever and I want to give my hubby a little baby because it's all he can talk about and he's so excited and almost giddy when he talks about it and it breaks my heart...