i might be pregnant idk what to do

i was a virgin and then had sex for the first time november 17 which was the day after i finished my period, the condom broke and he came in me. i took plan b not even 12 hours after sex. a couple days later i started spotting and the condom pieces came out of my body. it’s now december 12 and i was supposed to get my period yesterday and i’m late- why do i do. i’m young. please help. should i wait longer to get a test? what do i tell the guy? help.