implantation question

Is it possible to have implantation bleeding for more than 2-3 days? My "period" came a week early but it's been very light for about 4 days now (only needing a liner, which is unusual for me, I normally have very heavy flow even the first day), and I've had no cramps (also very unusual for me, typically I have almost debilitating cramps). That being said, has anyone on here experienced this type of bleeding in early pregnancy?