Hello,
I have been on both the clomid and the metformin. A lot of women have success on the clomid. The good thing about clomid that if it doesn't develop follicles they can keep increasing the dosage up to 150 - 200mg. You just have to be careful because the higher the dosage the more it can actually reduce your lining. I did not respond to the clomid but I also seem to have a lot of other issues.
Are you on metformin because of insulin resistance, or trying to lose weight? I took it after my miscarriage to help with preventing future miscarriage. They've done studies where it helps with that. While I'm not insulin resistant I still took it. I also didn't really need to lose weight but it still helped me lose a few pounds and keep it off without even trying.
Are you seeing an OB/GYN or an RE? I've been seeing an RE for about a year and a half but like I mentioned previously I seem to have more issues than what first met the eye. I know it can be extremely frustrating, I've been there, trust me. Its one of those things you just have to keep pushing forward and eventually you WILL get you miracle.
Good luck to you and please do not hesitate to ask any questions.