What Are The Side Effects Of Microgestin Fe 1/20 Birth Control?

Hi, I am almost finishe second month of microgestin fe 1/20 and was supposed to start my period today but it came Friday. So I did did not take my last birth control pill on Saturday. I was afraid it will mess up my period since it already started. Does it sound normal? And also, do I have to take fourth week of pills or could I skip them and start on my new pack as soon as my period ends? Thank you.