Implantation or period

OK GUYS. So I'm pretty sure this is my period but I want to be 100% sure. My period is always light on the first day, but I keep having thoughts in the back of my mind that this could be implantation bleeding... how can I be sure? It's definitely red, and it's definitely the same consistency as my period normally is, but I'm still somewhat worried. I was supposed to get my period sometime next week but it came early (the same thing happened last month so this isn't anything I'm not used to) Any thoughts??