I had my periods on 18 december. And I did unprotected sex for sometime on 24th december. Then I had diarrhea from 27 to 29 december. After that I had fever ,high cold and covid like symptoms from 5 to 10 december. For these I took fever medicine and cold medicine and also antibiotics. Now its 19 th january and till now I didn't get my periods. What could be the reason for late periods is it the medication, illness or I am pregnant.