Implantation bleeding?

Has anyone ever experienced implantation bleeding? What was it like? A couple weeks ago, my period was 3 days late and then just a very light bleed for 2 days. Does this sound like it could be implantation bleeding or just a weird period? I’ve been getting nauseous off and on the last couple of days and my lower back is hurting really bad. I haven’t tested (but I will soon probably)