Chances of me being pregnant?

I'm above the age of consent so no judgement please. My boyfriend and I had unprotected sex using withdrawal 10 days ago. About 3 days ago I woke up with my chest feeling sore. It was bad enough to the point where it hurt anytime anything brushed me (including my bra). I've been freaking out since then because I know sore breasts are an early pregnancy sign. Yesterday I took a test because I thought it may make me feel better. It came back a definite negative, but I'm thinking it's too early to be completely accurate. Any idea on my chances of being pregnant? Just a little extra information, but I can't tell if I am by my period because my depo shot wore off in March and I haven't had a period since. I'm asking on here because I have very conservative parents whom I would only receive judgement from if I voiced my worry.