Period

Why is my period always late? If I have sex I always use a condom. I just don’t understand why it’s always late. Plus ya know I use a <a href="https://play.google.com/store/apps/details?id=com.glow.android.eve">period tracker</a> and since I’m late every time it says I’m always probably pregnant. Is there any way to make my period come faster?? It’s has literally been 31 days since last period please help