late period

y

so I'm on the pill. I have been for over a year and my periods have been regular for a while and <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">eve</a> is good at tracking it. I am pretty good at taking pills on time. last pack I took like 2 in a week late. today, my period is 10 days late. my bf and I have unprotected sex, but he pulls out. I am 100% aware that pill+unprotected sex can lead to pregnancy. I took a test on Wednesday and it came negative. I'll test again and update later. the only thing I've done differently than usual is I smoked for the first time about a week ago. and have been every couple days, if that affects it at all.

im not stressed more than usual and there haven't been any changes in my life at all. why could my period be late?

also would it be too soon for a test to tell?