My period isn’t due till another week, how can I know if it’s implantation bleeding or can it just…

My period isn’t due till another week, how can I know if it’s implantation bleeding or can it just be my period came early? Normally period starts heavy the first two days and then mellows the last days to bearly anything.. and right now is just small amounts only no heavy so I’m confused. So can anybody tell me there experience from knowing the difference?