Late period + more sex?

Bethany
Catchy title huh 😂.
Basically, I'm late on my period after having unprotected sex with my SO, whom I've been with for 3 1/2 years. 
I'm supposed to be coming on, I've had sore boobs etc which is a sign for coming on your period, but we had sex again last night, and obviously did the deed.... I need some advice please people? Am I very fertile? Could I be potentially pregnant? C o n f u s e D .....