Faint positive followed by two negatives.

AF was due Oct. 5th. This past Saturday I took a pregnancy test around 8pm (used clear blue) It was a very faint positive. After reading about how blue dyes are bad about false positives I went a got a pink one. I took it around 10pm that same night. BFN. The next morning I took another pink one. Wasn’t the first time I peed that morning though. Another BFN. I’ve had cramping since yesterday and tomorrow it’ll be 39 days since the start of my last period. I’ve had lower back pain too. I don’t know when I should test again or if I should wait. Should I contact my GYN? 😩😩😩