Pregnancy

So I had sex 3 weeks ago we didn’t use a condom & I didn’t take a plan b. I was suppose to start my period 3 days ago so I took a pregnancy test because I was freaking out (it came back negative). But I “ started “ my period today only that it wasn’t how my regular period is. I’m just spotting & it’s a light pinkish/reddish color. Does anyone know what that means ?