What Causes Vaginal Spotting And Abdominal Pain?

I have been having some lower abdomen pain for a few days im not supposed to have my period till Saturday, i also have been having some spotting and i have been having unprotected sex. also i have an intense pain in the side of my breast and my pants are tighter. And i am so tired i struggle to make it through the day. how high is the risk that these might be some signs of being pregnant