Can Delayed Periods With Spotting Indicate Pregnancy Despite Negative HPT?

Hi, my girlfriend lost her virginity to me two months ago, we started unprotected at first, but not even a minute passed when I felt bad so I put a condom on and we used one every since. She had a regular period on time. Last month her period did not come (which usually comes around the end of the month). She took a pregnancy test after being a
week late which was negative. She is now two weeks late and she was spotting for one day. Could she be pregnant?