Period is 3 days late

Hey everyone:)

So my period was supposed to come on the 4th and today is the 6th (and it's now evening). And my period is no where to be seen. I was sick during the time I ovulated with an upper respiratory infection. The few days before I thought my period was due, my boyfriend and I decided to have unprotected sex for the first time. We did this for 4 days leading up to my period. I know it's not a safe method but we usually use withdrawal as a birth control method (bad. I know. But his pullout game is strong).

I haven't tested yet as I get home from work late and the shops are closed. and I don't have any symptoms other than a slight cramp in the left side of my body.

Any idea what else it could be? :(