How long does implantion bleeding last ?

I had a period last month but it was light but it lasted for 5days..but this month my period is 4 day late .

When the fertilized egg implants into the wall of the uterus some bleeding may occur. It is usually rather light,somewhat like spotting. As for a 5 day period. It may be possible. If you do not get your period within a day or 2 and you have been sexually active I would take a pregnancy test.
are you usually regular with your periods? If so then you know if this is irregular to u.