Could I be insulin resistant and still have regular periods? I have battled infertility for the past 8 years.?

I ovulate and have very regular periods. I have a cycle generally of 28 days and a luteal phase of 13 days. I began to TTC 8 years ago and was never successful until this summer (not trying) I got pregnant , then had a miscarriage at 6 weeks. Now we would like to try again, but we are having no luck. We do not have male factor issues, and my tubes have been checked. I have had thyroid testing in the past, but my new dr. ordered an insulin test to check for resistance. From what I have read, this is mostly related to PCOS, and most of the women with this do not ovulate regularly. I ovulate every month like clockwork. Could this still be the problem for me ?