Me and my boyfriend have been having regular sex for a while, and we always make sure to use a condom as I got told by my doctor I couldn't go on the pill as it will increase my chance of strokes. I am 16 and my periods are usually regular and if they are late it is only by a day or two. My cycle for this month is 31 days and I don't know if I should be concerned? Could someone please give me some advice, thank you