I restarted my period less than a week after stopping it?

I was wondering if this has happened to anyone else. I started taking Cerazette (birth control) 6 weeks ago, and at first had my normal period, except it was only 3 days, from the 3rd to the 5th of May.

My GP did say that my periods could change to anything; they could get longer, shorter, or could just stop altogether. Obviously I thought this was fantastic news as soon as I stopped my first period as it's so much shorter.

But on the 26th of May, I started again, and again, nothing changed except the length. This time it was exactly a week long, then had some brown discharge which isn't really abnormal. I stopped this period on the 1st June, and now it's back. I started again on the 7th.. 6 days after my previous one stopped.

Has anyone else experienced this, or is it something I should talk to my GP about?

I should note that the last week or so I've been up to 3 hours late taking my pill on some days, since it's the holidays and my alarm never seems to wake me up. But I did Google it, and apparently it's fine to be 3 hours late.

Any help?