Period weirdness

Zoey
So. My cycle usually comes around the 10th-12. But back in May it switched up on me and was a couple days early. Now it starts earlier. 
So last month it came like it was supposed to. Then it came again later. 3 days early October 27-November 2 
My Glow calendar says it was supposed to come yesterday. Can anybody help?? 
Yes I have a boyfriend, no we don't use condoms 😮