You should always take your pills on schedule, regardless of your period. When you interupt the regular schedule you lower the effectiveness of the birth control. If you do not have a period during the week of inactive pills, start the next pack regardless. Even if you are pregnant, there are no known side effects of continuing on the pill until you are sure that you are pregnant.
There can be many reasons for not having a period while on birth control, pregnancy being a slim one. If you have started a pill pack late, or not started a new one on time please be advised that you should use a back method of BC (like condoms) for the month.
Please call your doctor to keep them updated on the status of your periods as this might be caused by something like PCOS or a horomone imbalance. They can also advise you on what to do if you have not kept on schedule with starting a new pack.
Take a home pregnancy test, just to be sure. If you are 10 days passed the day of your missed period, you will be able to have an accurate result. Buy a 2 pack just in case one is defective, or you feel like you need a "second opinion"

. Take the test first thing in the morning, with your first morning urine as this is when the levels are highest and will help with the accuracy of the test.
Good luck!