please help! Late period

I've been on the pill for 2 years now and have gotten it at the same time and day, every single month. I was supposed to get it today and haven't and I'm freaking out. I haven't had penetration sex with my BF but there was naked grinding and his I'm got on my inner thighs.. my mom told me that it's normal for my period just to be late sometimes.. has this happened to anyone else and it ended up coming??