Pill but no period

Shelby • Alaskan, I love makeup and anything beauty.
So I lost my virginity almost a month ago, and I've been on the pill for a year and a half now. When we have sex my boyfriend and I don't always use condoms and he came inside me 2 times, I'm 4 days into my placebo week and I haven't gotten my period, but I took a pregnancy test and it was negative. Should I be worried??
UPDATE: I got my period 2 days after I posted this