Pregnancy test or nah?

So recently I lost my virginity to my long time boyfriend. It was my 19th birthday and exactly 8 days after my fertile window was said to have ended. I got the notification my period should be starting 2 days ago but I have yet to have any bleeding at all. I am kinda really freaking out and this being my first experience with this type of situation I don't know what to do. Any help?