According to the data you provided (had an abortion on December 3rd, had light bleeding after 6 or 7 weeks and nothing else), you might have experienced amenorrhea.
Amenorrhea is the absence of a menstrual period. It might be primary when there was no menstrual period at all or it might be secondary when there was a menstrual period at one point in time but it stopped for different reasons.
It is not uncommon to experience amenorrhea after taking oral contraceptives. Oral contraceptives contain hormones that are created to affect the regular hormone production pattern. In certain cases, this might last longer (sometimes up to several months). However, if you miss your period for more than three months, you are advised to visit a gynecologist for a physical examination and hormonal laboratory tests in order to check for a hormonal imbalance caused by the oral contraceptives. If a hormonal imbalance is detected, the doctor might recommend other hormone-containing pills that are supposed to restore the normal hormone production pattern.