implantation bleed?

Hey. My cycle is around 29 days I was due to start today but started 3 days early. I had mild cramps compared to usual and was medium flow which was a brownish colour. Then the day after very light and light brown, and then 2 days I've had tiny brown spots when wipe but not needed to use a panty liner or anything. Has my period came early or could this be implantation? Is it normal to last this long