So confused!

12 days late and I’m never late, negative HPTs, and a whole lot of symptoms. I’m nauseous all the time, sore breasts/nipples, darker areoles, cramping, insane amounts of indigestion, super tired all the time, back pain, etc etc etc. I have an appointment but it’s not until Thursday. I’m so confused about how all my tests could be negative, how long did it take for you ladies to get your positives? Is it possible for me to be pregnant even with the negatives?