Over thinking much?!

My ex and I had gotten back together recently and we ended up having sex on the 16th( after sex I had major cramping) . Thought I was in the clear of ovulation but I guess I wasn’t? I’m supposed to get my period today but have no symptoms. Normally get them a few days before I get my cycle. I’m trying to think positive about everything but I have so much stress and I think it’s delaying my period. Can I have thoughts? Please be positive TIA