pregnancy symptoms but had period?

so I got my period around my first or second white placebo pill in my last pack. they're actually not sugar pills, just a pill that has progestin and no estrogen. it was a light period, only needing one tampon or one or two pads during the whole day. lasted about 4 days and ended around when I started my new pack of pills. I'm still experiencing weird symptoms though. I just started a new brand of birth control this past week. could that be it? I've been super bloated and my boobs have been really sore. thoughts? :(