Implantation bleeding

Earlier I thought I got my period. I was cramping then went to the bathroom and saw brown blood. I put a tampon in and I started to feel uncomfortable. I went back to the restroom and took the tampon out and saw brown/pink blood. Usually went I start its very heavy. So is this implantation bleeding or is my period coming?

Im about 5 days before my period. Also I am still cramping and feel gassy