Need help on knowing if imm pregnant

Patient: I had unprotected sex two days before my period .. it came on but I was way lighter than normal and only lasted 3 days could I be pregnant?

Symptoms: None

Doctor: Hello,If your menses after 2 days of having unprotected sex and lasted for 3 days, then it itself ensures that you ar e not pregnant as the endometrial lining from the previous cycle was shed off with menses terminating any chances of pregnancy even in cases of late ovulation.So rest assured.regards