When will this end?

So this is my first time I’ve tried skipping my period with birth control pills (starting a new pack right away instead of taking the placebo). I got through the week just fine, a couple bobbles here and there but nothing too late until the last day I was at a friends and left my pills at home. The next day I had cramps and regular PMS symptoms. I started bleeding a little the night after. Is this the start of my period or breakthrough bleeding? Should I “go back a week” on the pills if it is the start of my period? I’m so confused.