I would contact your gyno, I was told that if metformin didn't work I would be given clomid to "kick start" my cycles, as for when you should take it I have no idea. And in this situation it is definitley safest to talk to your gyno, as even though there are some of us on clomid he may have reasons for doing things specific to you. If that makes any sense.

Goodluck!

*hugs*
Cailin