Why I cant get pregnant?

Patient: I am 26 yr old and my husband is 27yr.We are trying for a baby but so far it hasnt been successful. My periods are every 28 days for 5 days and they are regular and not heavy. We consult gynacologist. She made all checkups and every thing is normal for me. But my husband’s semen analysis report shows that his sperm are moderately active and he have mild left varicocele.Doctor prescribed Heyforte tablet for him.I had 3 clomid cycles now.In the third one i had one fertigyn 5000 injection.But no use. I dont know why I am not getting pregnant successfully.