I feel like a failure as a woman

My husband and I have been trying to conceive since January. Every month I get excited and hope that this is our month. We were able to get pregnant with twins in April but we had a miscarriage in May. It has been so hard to get pregnant again. We really want our first baby. My cycles are usually about 38 days. Every month we use ovulation tests, both healthy, and we've tried preseed. What has helped for others?