Could I be pregnant?

Patient: My last period was June 16th. According to my app I was due yesterday. However, I had unprotected sex last Sunday. Could I be pregnant? He withdrew as far as i know of. I’m too embarrassed to buy a test because we live in a small town and everyone knows my mom. We had sex unprotected last month a week before my period and it came. My period comes 1-2 days late. When should I really be worried?

Symptoms: For the past week I’ve been having stomach cramps, headaches, diarrhea