Hello, My Girl Friend And I Are A Bit Worried

Hello, My girl friend and I are a bit worried about if she is pregnant, we dry humped last thursday with only panties and I had my Nike Dri-Fit under wear on we were both wet by the end of it...an my wet underwear was touching her wet panties.....will she get pregnant? Or should we be worried? Because she took a pregnancy test on monday and it came out 53% negative but it may be a false negative. I just don't know whats going on could you enlighten me?
Thanks
-Sammy C