Bleeding not a period.

I'm 23.. Have regular periods always last three - four days, normally light to medium.  I had my period, it finished after four days. 6 days later I have started heavily bleeding.. I have no pain, nor do I have eggs like a normal period. The blood is different, it's bright red! It's happens since Friday (it's Monday now). I've been on a new contraceptive pill for a month now.. Could it be this? I haven't had sex so it's not implantion bleeding.