Late/Missed Period. Period being late?

Doctor, my last period was from March 5th to 10th and my cycle usually ranges from 27 to 28 days and not more. However, I was due on 3rd of April but I haven't had my period yet. It brings me a great concern as it has already been seven days since my due date. I tried paying Practo and reaching out to a doctor but however, the doctor did not understand any of my query and was not helpful at all. I have never experienced this before and it brings great dilemma and hence this question. I am sexually active but however, I have never had unprotected sex. The last time I had sex was on 16th April. It is very difficult at this hour to go out to a medical since I live in a hotspot area which has been completely sealed. Please suggest me what to do. I haven't tested myself for pregnancy yet and I haven't taken any medication. Also, if I am pregnant, till what time can I abort using abortion pills? Would there be any other reason for a my period being late? Also, I am under alot of stress.