*18 DPO but BFN

So according to this app I’m 18dpo.

On November 20-21st I had sex with my boyfriend. Evening of the 21st, I had egg white cm so I figured I would ovulate in that general time period. Well fast forward to now, I have taken 2 different pregnancy tests. One being when I was 9 or 10 dpo. Then again at 14dpo so Monday. Kind of just defeated at the negative tests so I told myself I wasn’t going to test anymore. Well I still haven’t gotten my period, and my cycles range between 30 days to like 33-35 days. So I’m guessing I could have ovulated later and I’m just out this month? But I had the change in cm on the evening of the 21st. I feel like if I was pregnant it would have shown on the test on Monday? Idk :( with my son I didn’t have any symptoms until I knew I was pregnant. And even then I tested when I was a week late and had a STRONG positive. So I’m not sure. Any advice? Sorry it’s long.