Early signs of pregnancy?

Natalie
I am supposed to start my period in four days, the 31st. My boobs have been sooo sore for about 3+ days. I'm exhausted all the time. I want to cry at everything. I am extremely constipated. No cramps though. 
We had sex at my highest risk day without a condom but he pulled out. So we're wondering if maybe I'm pregnant. 
Should I take a test now or wait a couple days or wait and see if I'm late?
Thanks!