feeling helpless

I hate that my doctor pretty much told me he didn't know why we weren't getting pregnant. We have been trying since 2014, I'm 28 and my husband is 24 we are pretty healthy. I do have endometriosis and PCOS, I have pretty regular periods. I had hystosonagram and hsg tests done and all those came back good. I do have an insulin problem so I was put in metformin. My husband has a low count and low count of good swimmers but my doctor doesn't seem like it's a problem and we shouldn't worry but does want him to take vitamins to help boost his count. We were told iui is our next step. Has anyone have an iui and did it work it for them? What else have you done to get pregnant before doing iui or ivf? I just feel so helpless right now. Sorry for a long post I just don't have any else to talk about this.