You dont have to take that last week of pills... There's nothing in them, hence they are called sugar pills. They are there so you remember and stay in the habit of taking your pills at the same time everyday. I usually dont bother taking the last week of pills because they aren't necessary.

Since it was your first month on birth control, that is why your cycle is a little messed up. Your body is still adjusting to the hormones from the pills. Dont freak out, you're fine. It'll take a couple months for things to regulate.