It is probably delayed sloughing of the endometrium. If it continues or gets heavier I would see a doctor. Also, if you have any other symptoms such as pelvic pain, foul smelling discharge or itching I would go in to the doctor.
mkh9
It was a day after my period. is that normal?
Well it depends on your age and how long after your period it was. If you are perimenopausal it is typical. If you are younger or post menopausal but it it a day later or two it may just be some delay sloughing of the endometrium. Also, birth control pills (if the dose is wrong) can cause some spotting. If none of these apply you may want to have a pelvic exam if it occurs again or just to make sure you are ok. Any pelvic pain or other problems? At least that is my take on it.
take care,
mkh9