Your halachic status depends on how long after intercourse you cleaned yourself off. If it was not immediate (within seconds), then you may disregard what you saw.
In any case, it is important that you see a physician to rule out any condition which may require treatment and to find if there is a non-uterine cause of bleeding. Also, if you did wipe immediately, then identifying a non-uterine source of bleeding may give you grounds to disregard the discharge you saw.
For the future, we recommend not performing a bedikah before speaking to a halachic authority. A bedikah cannot undo niddah status, but can sometimes make a woman niddah.
Please write back with any further questions.