spotting

i have never spotted before , and i spotted yesterday, it wasn’t a lot , not enough for a tampon and it was brown, and i had unprotected sex 3 times during my supposed ovulation according to this app and flo, so i took a pregnancy test that night and it came out negative , i haven’t missed my period yet so could the test be a false negative since it might be too early or is it a true negative ? please help.😩