starting a little late?

I have been on the pill for almost a year now, but due to a mix up in mailing addresses, my pill packs are going to arrive a little late. I am getting my period this week and my pills might not get here until next week or the week after. Is it okay to start the pill then or do I have to wait until the following period? I have ovarian cysts that the pill is helping to control the pain caused by them and when I am off the pill I am in a lot of pain. So if someone could let me know about my question I would really appreciate it!!!