Question ladies…….

My period came 4 days late.. it finally started Sunday 9/12 but it only lasted for 3 days which is unusual for me because my menses usually last for 5/6 days… I am currently spotting. Could this be a sign of implantation bleeding and should i take a test? There was no change to my diet i do have a over active thyroid but even with it being over active my period still came on time and lasted for 5/6 days