Hi. I Had My Period On April 6th It Lasted

hi. I had my period on April 6th it lasted about three days. it was very light at first and then got heavy. today is the 22nd and for the last three days my breast have been feeling full and sore, and now my nipples are starting to itch. Today I noticed that my stool has is been normal but very green. I have not had a change in my diet ( aside from drinking less pop). my question is. could I be pregnant? and how soon can I test? also I do not have insurance to go to the doctors right now.