I'm on Mircette birth control, which regulated my periods very well and I was always able to tell what day I would be getting my period.Here's where the problem started - I was on vacation in late November and forgot to pack an extra package of pills. I was one pill short so I had to go a night without one. The next day when I got home I promptly made up for the missed pill and took two. I thought all would be OK because normally it was when that happened.Anyhow, ever since then, I can't tell when my period will come. It used to be when I reached the last 4 yellow pills in the pack, my period would be there. Now it's haphazard and just comes when it comes.Why is this? That one missed pill wasn't the first time I had done that, and I never had a reaction like this. Should I get my hormones checked?