HELP !!

I had the implant put in not last Friday the Friday before , and had unprotected sex with my long term boyfriend when I was drunk (4 days after the implant was fitted ) and my period is a day late. I'm probably over reacting but I'm scared as hell I might be pregnant , yes I know what I did was stupid and have to wait 7 days but I'm really terrified, I've had pms symptoms like moodiness and cramps but nothing ! I'm really scared , is this normal for girls who just started the implant or am I pregnant help ! I'm 17 and have never had any desire to have kids ( atleast not for a long time )