Implantation Bleeding Or Period

My period is supposed to come on 29 May. But till now no signs. However, there's some light pink bleeding since 27 May. It comes and go. And the bleeding got heavier but not more than a panty liner. Bleeding stopped on 1 May. I don't think that is my period as the flow is too little. I tested this morning but negative. Just wondering if I had my period or is it implantation bleeding?