On birth control. took some pills late, so i messed up having my period on time. i am not pregnant. my period shouldve started thursday or friday. i have cramps and everything else but no bleeding. should i still start the new pack on sunday?

Sounds ok: If a person is positively not pregnant, it should not matter when she starts a new pack of birth control pills as long as it is on a day that helps her remember to use the pills properly. Thats why starting on the first day of the week (of the calendar she uses) is helpful. If no withdrawal period after the 21-24 active pills, she can do a home pregnancy test.