It could be implantation. Implantation bleeding occurs when the fertilized egg implants itself in the uterine wall, and it usually happens about 7 to 14 days after conception. If this bleeding is from implantation, it will be more like spotting rather than a steady flow of blood you would get with your period. I would wait to see if you do miss your period. If you do, then I'd advise you take a test.. Good luck!
Well it could be. BUT not likely since you had just ended your period the day before.