if i don't start my period while on the pill?

so i had went to the obgyn to get on birth control because i had skipped a period for three months. i had ended up getting my period, and started the pill the sunday after i finished my period. i've been sexually active. i've been taking it for a month now and only have a few reminder pills left. My doctor said it may take a few months to regulate my period, but what happens if i don't get it at all?