period wierd

So I have been on birth control for 5 months and i was originally a light bleeder and the birth control reduced my period a lot. For he past month I have Excersized 5 days a week. Now this week I have a cold and my period has been so light. Like I have only bleed enough for a full pad in the past 3 days. I always take my pill within a hour and I have never broken a condom but should I be worried?