Missed Period

Hello! So I’ve only just begun taking birth control (Lo Loestrin Fe) last month and as I reached the four “placebo” pills, I didn’t have any bleeding. It’s been about a week since I was “supposed” to get my period, but I haven’t gotten it and I’m 9 days into the next pack of pills. Is it normal to not get a period when you start birth control? I took a pregnancy test a few days ago and it was negative. Thank you for the help in advance!