Am I Pregnant???

Help me out ladies. I’m 17 and currently living with my parents (me and my boyfriend plan to get a place together when I’ve finished college) but my boyfriend still stops over. I’m not on the pill (I always use a condom) but the other night when me and him got a bit frisky the condom came off halfway through and we only noticed a good 10 mins afterwards when he pulled out whilst ejaculating. My period is now 12 days late (it comes every 35 days). Am I pregnant??? I took two tests and they both came back negative btw but I know the only true way to know is through the doctor.