This past month i switched from one brand of birth control pills to another. my period is late; are late/missed periods possible/normal considering?

Yes: Changing pills can take awhile to adjust. It is more common to have break thru bleeding but with some of the low dose pills periods become extremely light. Let your doctor know. It may mean you need a different pill. It is unlikely that you are pregnant if you have taken all the pills right, but a pregnancy test would be a good idea just to be sure.