What Are The Side Effects Of Contraceptive Pills?

hello, i was just curious as to whether you could help me, im taking the contraceptive pill and have been for the last 2years with out stopping however i had my period almost 2 weeks ago but then halfway through my packet of pills i started bleeding again is this normal? i havnt missed any pills its a continuing thing but i dont understand why im bleeding? is there a chance that i could be pregnant ?