Pill and unprotected sex

I've been on the pill 3 full months. For 2 of those months my period has started the same day of my inactive week of pills. I kind of suck at taking my pill on time, even with a reminder cause you know life sometimes. Sometimes it's only an hour I forget, sometimes up to a whole day. How likely is it I could get pregnant because of this. My period is late this month and I'm a worry wort.