I'm 27. I Have Irregular Periods. The Day First Day

I'm 27. I have irregular periods. The day first day of my last period was February 8th and then January 12 before that. I had unprotected sex on the 12 of February and then again on the 23rd (which is supposedly the start of my fertility window)..


Is there a way of knowing my before my period if I'm pregnant? The anticipation is killing me.