how many weeks am i

there's a reason i'm not going to the dr yet, which i'm going to in 2 weeks but i sorta wanna know now. My last period was December 5th (that's when it started) it ended on the 9th. my fertile window was the 8-15th of december... how many weeks would i be? i know for sure i'm pregnant? i just really wanna know now i'm new at this so i don't know