Late period!

I ovulated on the 15th according to the app and had sex the 14th and 15th. My period is 99% on time every month and I’m now 4 days late. I’ve taken a PT every day my period has been late and they’ve all been negative. I have no signs (cramping, breast tenderness,mood swings,acne) like I usually do that indicates my period is about to start. Is it possible I ovulated later than I thought and I’m testing to early? My first baby I tested the day my period was supposed to start and my second (unfortunately MC) I tested 2 days before I was supposed to start and also got a positive. Should I wait a little longer and test again or should I go in and see my doctor?