Is Light And Discolored Spotting While Due To Withdrawal Break From Pill Normal?

I'm on the birth control pill, microgynon 30, and have been on it for around 8/9 months now. I took the pills back to back the last month so i did not have my normal withdrawal bleed. I do occasionally have problems swallowing pills, and therefore sometimes crunched them in my teeth. Also i started this pack late evening, where i normally take the pill when i wake up and have taken other pills in the evening not the morning. I am now currently in the final stage of the second pack, i am due to start my withdrawal break on saturday, yet i have recently had spotting. It is not like a normal period and is incredibly light and discoloured, not red. I have had this for around 3 days now. What could this be? Is there a chance this could be a sign of pregnancy? Or is this a normal occurrence, any help would be gratefully received. Thank you