Spotting ? BFN ? Missed period

Hi everyone . My bf and I had unprotected sex during my fertile days . We use the pull out method. The first time was during the beginning of my fertile days and he told me he may have came a little bit inside of me. The second time was a few days later where I know he successfully pulled out. My period cycle is usually 24-28 days. For the past 6 months they have been on the shorter side though. I’m on day 28 with no period still. Although the past 3 days I have noticed spotting. First day was a small amount of dark brown. But today it was a small amount of tan discharge instead. No other symptoms besides cramping for the past week on and off. I’ve taken a few tests and all are BFN. Also was crazy and checked my CP today and it was high and I believe open ?

Chances of a positive ? thnx ladies :)