False negative? Premom Amazon tests

I’ve gotten 3 positive tests on frer test (faint, but clearly there and have color), but on my premom tests, they’ve all been either EXTREMELY faint, or negative. I have an appointment Monday to get my blood drawn, but I don’t know what to think! I think I’m pregnant, and having symptoms, af supposed to come tomorrow, but the strips being negative is throwing me off and idk what to think! I’ve searched the reviews on Amazon, and a couple of people had an issue with these tests giving them false negatives, even when other tests were clearly positive