Implantation Bleeding Question

Hi everyone,

I’m currently 4 days late on my period. I’ve been experiencing cramping, very slight nausea (like barrrrrely there) and dizziness. Today I notice when I wipe I have very light, brownish colored blood. So my question is, can implantation bleeding happen after you’ve missed your period? Ive taken 2 pg tests (one yesterday and one the day before) and both were negative.