Plan B making period late?

zoë

I took a plan B immediately after having an “accident.” my period is 8 days late. I took a pregnancy test and it was negative, but I am still worried. Has anyone’s ever come this late after taking plan B? I’m also under a lot of stress so that may be a cause too but I am still scared 😬 I took it like four weeks ago, so I feel like if I was pregnant it would have shown positive because that is time for the HCG or whatever show up, right?