Late period

I am 7 days late on my period. I took two pregnancy test which came out negative. My period has been off lately because of going between birth control, I had ran out of birth control and had to make an appt last minute it was the same brand as my regular birth control just a different color so I didn’t know if it would bother my body. Since then I have been off on my period. I didn’t know if I should wait a few days to see if I start or go to the doctor to be sure.