Help me. Don't know

Katrina
So I need help... Should I go to the doctor to get blood work? I had sex on 25th which was 2 days before ovulation according to my days app. My period was due on the 12... I took 3 pregnancy test since the 13th. Negatives. But I still haven't started my period. My nipples are sore. I get sharp pains in my stomach. What should I do?