When am I going to ovulate??

My period is ALWAYS regular and comes the exact day it’s predicted to, BUT of course I’m now 7 days late. We had unprotected sex the day my period was due and everyday since then. I don’t know how I could be pregnant obviously as the day my period was due was the first time we had unprotected sex as we decided to start trying. but any thoughts on why as soon as we decide to try my period screws up and I won’t know my ovulation days 😱😱😱😱😱😱 (btw I did take a test today just to double check and it’s neg)