I am 27 and i have been trying to conceive but my period just started after a 7 day delay whereas i had all the pregnancy symptoms. why?

Early pregnancy: Sounds like you need to be evaluated by a physician to make sure you are not have pregnancy-related bleeding.

It depends.: Because menstrual cycles are influenced by normal fluctuations in hormones etc, almost every woman will have a late period from time to time. Occasionally a late period is caused by an early failed pregnancy. This would explain both a late period & pg symptoms. Even otherwise otherwise healthy women with regular cycles might not achieve a pregnancy right a way. Don't be discouraged.