Is this implantation?

Well, today I am four days late for my period (which I've always been early, never late.) pregnancy test today was negative (used a dollar store test) I have been cramping for the last 24 hours and had like a tiny bit of pink and brown just now. Sound like period or implantation bleeding?
​What has thrown me off is that I haven't had any of my pre-period symptons...even this cramping doesn't feel like my normal period cramping.
​Planning to test tomorrow if I don't fully start.