I had implantation bleeding about 2 weeks before my period was going to arrive. It was a tiny bit of blood and went away within an hour. It may be, it may not be. The only way to really know is if you miss your period.
Here is an informative website! http://www.gynaeonline.com/implantationbleeding.htm
It very well could be... I know it is awful but implantation bleeding is only something that can be accuratly labeled in retrospect, so that only way to know is wait a few days and test. I would say that you could reasonably test 2-3 days after you notice the bleeding, if it was implantion.
The other option is that it was ovulation bleeding, is that a possibility??