If you are worried that you are pregnant, talk to your personal physician. They can do a blood test that will be accurate within a few days of implantation. You can also do an OTC urine screening right now, and 1 week from now. If both come back negative, then there is little chance that you are pregnant. You failed to mention your age. If you are under 20, there's a chance that your cycle is still stabilizing. Have you recently started or stopped using birth control? This could also affect your cycle. A large amount of stress can also affect early bleeding. If the bleeding persists for longer than a normal cycle, I'd recommend mentioning it to your OB/GYN or your family physician. If you start experiencing any sharp cramps that would be out of the ordinary for a normal cycle, then I would also recommend medical attention.