PLEASE COMMENT NEED HELP

anon
on october 1. i had unprotected sex. on october 7. i had a normal period. throughout oct. i felt fine, just gassy and stressed. this month is the firs time i've tracked my period. it's now november 7. and my period didn't come on the exact day as last month. could i be pregnant or just scaring myself? i don't know much about the mestrural cycle