I need some advice.

Anne
This is the thing. My period's supposed to come 4 days ago but eventually it's not yet coming. I have this tracking apps which I downloaded before in my phone that helps me in regards with my periods. That's why I thought of my period is late for 4 days now. 
I've been experiencing breast pain as if it's like swollen. I have this little cramps and headache and back pain. My discharge is white. 
I had my period last July 3-8. Is it possible that I'm pregnant anytime soon? I'm so worried.