help please

Annalise
Typically I get my period when <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">Eve</a> tells me I have 4 or 3 days left. My period is one day late according to the app but 5 days going from what usually happens (it's day 31 btw). My boyfriend and I are sexually active and have always always used a condom and I make him pull out with the condom still on half the time because I'm terrified of becoming pregnant. I've been having cramps for the past week, but I haven't started bleeding yet. I usually only get them the day or two before. I'm really stressed out because I'm afraid I'm pregnant or that there's something wrong with me. I was supposed to start birth control once this period starts, so I'm also stressed because my mom keeps asking if I've started yet so we can call to get the pills. is my stress delaying my period? I might take a test tomorrow but I'm honestly too afraid to because I don't want any of this to be real. I'm 17 and I've had my period for 6 years so it's pretty regular by now. what do you think?