AF arrived! 😩😩

Once again AF has appeared. We have been ttc for 7 months now on baby #1. My husband and I are both 29. I know they say it can take up to year for a healthy couple to conceive but I'm starting to feel like there is something wrong with us. What are we doing wrong? I use the opk to determine my fertile days. I still eat quite a bit of sugar and I'm not that active. My stress level is a bit high cause I'm still in school. Any advice