What Are The Side Effects Of Taking Norimin?

I've been taking 'Norimin' for 2 months today, and I decided to skip my period, and opened a new pack and took a blue pill instead of starting on the red ones. I haven't had any side effects since I started taking the pill and I used the red pills the first month when it came to the time for my period. When I took the blue pill this morning, I started bleeding lightly. Is this my period or side effects? Also should I carry on taking the blue pill or start the red ones tomorrow?