I'm On The Cerazette Pill, Been On It For About

I'm on the cerazette pill, been on it for about 8 months, and I've had no periods at all, until this morning, I woke up with red blood, then this after noon it went brown, then tonight it's gone back to red blood. Over the past 2 weeks I've had on and off sore boobs. I'm kinda confused why this is happening? I am taking my pill every day, but taking them all at different times of the day? can you please give me some advice why this might be happening to me? Thank you.