Am i pregnant?

So I am on birth control and I have had sex with out a condom, but he did not finish in me. I had my period, after a few days off my period my stomach started to have some pain and my breast were getting sharp pain in them. I then started to get worried so I ran to the store and got a pregnancy test (I got the first response 3 test one) and it was negative. I don’t have sharp pain in my breast really anymore but my stomach is been getting weird pain. Do you think I could be pregnant? Should I go take another test to double check?