What happens if i miss my period two times while on the 28 pack of birth control pills?

Two possibilities: These days, birth control pills are very low dose; however, if you are lucky, & take you pills every day at the same time, there is the possibility that the pill can progressively decrease your period frequency, amount, and duration to the point that you don't bleed at all. Then, you just look for other signs of pregnancy. Keep up the great med compliance. Either that, or check a pregnancy test!