I understand that you are anxious, but there is no reason to be worried. The light period is due to the effect of the oral contraceptive used. When you are on the oral contraceptive pills they generally cause a hormonal imbalance that results in bleeding between periods. This should gradually subside and your menstrual cycle should become normal.
If the bleeding doesn't subside after the next menstrual cycle, then you could consult your doctor and she could help you with it.I hope I was able to clear your queries.