Implantation?

tabmb
Has anyone experienced implantation bleeding that was heavier than spotting? 
My period was supposed to be due this Sunday (14dpo). Instead, at 9dpo I started having medium cramping and bleeding about the same as my period would look. It lasted through 10dpo and turned to light spotting by 11dpo. Today is 12dpo and I tested bfn this morning. 
Would you assume that was just an early, short period?
Anyone else had heavy implantation bleeding?
Thanks guys. 🙂