Birth control and pregnancy?

I wanted to post this to ask you guys, because I'm not sure if it was a coincidence or something common. So anyone that has had a similar experience or knows of someone please let me know! When I got pregnant with my daughter it was a result of a missed BC pill. I had unprotected sex that day, and right after I was pregnant. Now I've been TTC about a year & have had no luck! I'm not taking any BC. & we always try to be intimate on my most fertile days. At one point I was an entire month late, and I was very excited! But nothing. Just an irregular month. I've been wondering if maybe taking BC to regulate my cycle & then having sex on a missed day again would work? Has anyone tried this?