Hi sis! Okay so yan talaga ang confusing part, sometimes super early pa ang hCG levels so negative ka ngayon but positive kaagad the next day, lalo na kung gabi ka lang nag-PT kagabi tapos ulit umaga na ngayon, kaya dapat reliable talaga yung brand at timing ng test. A few of us din nag-experience ng ganyan, especially if mabilis mag-implant or may spotting pa after intercourse, pero yung most reliable talaga is mag-blood test sa clinic kasi that can detect even lower hCG levels, mas maaga guaranteed. I'd say best mo na mag-check with your OB para sure at para ma-rule out din kung normal lang yung spotting, kasi mixed with the positive-negative results, better safe na mag-consult na para ma-confirm kung naka-conceive ka talaga or not!