My period came 3 days early light and pink it never comes early. i had unprotected sex. my period is never this light. what could it be? implantation?

Check a test: It could be implantation bleeding, but you can check a pregnancy test at his point to find out if you are pregnant.

Could be: Light bleeding 3 days before your period is due could be implantation since you had unprotected sex but it also could be some of the normal variation in cycles. To know for sure, once your regular period is late, check a pregnancy test and repeat it in 3-5 days if it is negative. Hope this helps.