Symptoms of pregnancy or period?

So I have had endometriosis for about 6 years I have had surgery twice and had my IUD removed back in December 2017. I am due to start my period in about a week but I have been cramping and my nipples have NEVER been this soar. I was worried about my endometriosis coming back and thought that was what was causing my cramps but now my nipples hurting the way they do has me questioning if I’m pregnant. I want to test but feel even if I am pregnant it wouldn’t show up on a test anyway.

Has anyone tested a week before the period and gotten a positive??