I need some advice please...

3 years ago in December we lost our baby at 11 weeks. We have been trying for a baby ever since. Tested my boyfriends sperm with a home kit today and it came back as normal. We have been working out ovulation dates etc every month, But still no luck. I have never had any abnormalities with my periods (always been regular and no concerns). What could be stopping us from getting pregnant? Could it really be me as my boyfriend came back normal... even when I have no causes for concern?

I am 21 and my boyfriend is a few years older. Any ideas on what we should do next?

I am so heartbroken and think about this everyday, it’s taking over my life I want this so bad!