Can anyone tell me whats going on?

I was 2 1/2 months late on my period and it finally came the 11th and ended on the 19th, well I just went to the bathroom and saw blood in my underwear and wiped and im bleeding again, what could this mean? I'm not cramping or anything but this has never happened to me and ive never been this late and I know i wasnt and am not pregnant. Can someone tell me what might be going on?