HELP! AF or implantation bleeding? I'm only 17

On the pill, missed one 6/1
Took 2 the next day, but still had sex w/out condom both days
Last period ended 5/20
AF 4 days late
Super light brown pink discharge w/ metallic smell
Is this implantation bleeding or is my period starting?
Picking up test tomorrow but I'm really scared
Could I be pregnant???