Pregnant??

Okay so I had sex the day after my period ended(it ended 10/19), my next period ain’t due until 12 more days, but I been feeling extremely nauseas the past few weeks, & bad period like cramping in my uterus...so my question is has anyone gotten pregnant the day after their period ended?? How long did it take you to realize?? I have one pregnancy test, but I’m not sure if it would be to early to test or not so I don’t wanna test if it’s Gunna give me a nonaccurate reading if it’s too early..