27 days late

Hello guys

Im freaking out because im 27 days late, I’ve taken MULTIPLE pregnancy tests, gone to the obgyn May 21st for a urine test came back negative, NEVER HAVE I EVER missed a period. Could i possibly be pregnant? At this point im losing my mind. I started birth control april 6th for the first time but stopped taking it on April 29th to see if my May period would come but it is now may 27 and absolutely no sign is this normal? Please ease my mind, i am 21 yrs old.

Thanks and blessings