12 days late and no bfp

Camila
I was supposed to get my period Dec 29 and it didn't come. I'm 12 days late and I have has 3 bfn. I have a doctor's appointment on Tuesday and idk if I should ask for a blood test or ultrasound. How long did it take for you to get a bfp? Only symptoms I have is the missed period and I'm really really tired everyday. Any suggestions?