Period is late, worried

Patient: I had unprotected sex on June 10ish 3-5 days before my period was due. I got my period after 3-5 days. I started working out for 2-3 weeks and lost around 2kg. I’ve also been stressing out because of school. I got worried as there was no signs of my period coming and took 3 tests in the past 2 weeks and they were all negative, but my period is still not here. (Was supposed to come around 1-4 days ago. Could I be pregnant? Should I be worried? Or could it just be late due to the stress?Thank you

Symptoms: Late period

Doctor: