What Causes Vaginal Spotting With No Regular Period?

I am 25 years old and my period is always on time. I am late by 2 days for my period which was due on the 28th. It is now the 30th and around noon I started to see blood but only when i wiped after using the bathroom and it is now 5 30 in the evening and the same thing is happening. Is this implantation bleeding or the start of my period?