Birth control or pregnant?

Hi I recently started back up on birth control after 7 months because I was not able to afford it. I started on my first pack 17 days ago. I was supped to start my period 8 days ago but it has had yet to show and I thought that that was be because I haven't taken the placebo pills but now I am worried. I now have been feeling a bit queasy and bloated for a few days. I read that this could possibly be side effects from the pill but I didn't have any of those symptoms last time I was on the pill. Please help !!