please respond!

okay so to make it short and sweet, i had protected sex with a condom and to my knowledge nothing went wrong. this was the 5th & 14th of december, and my period is due january 1. i have been feeling dizzy, had unusual gas, and have had a headache a couple times along with one or two hot flashes. i know these could all be sporadic and nothing to do with pregnancy, and i’m hoping that’s the case. is it way too early to be feeling these things and i’m just making it up in my head? any advice would be appreciated :/