Could I be pregnant?

I got my mirena taken out in June... Had some bleeding a few days later ( June 27-30) and then got my period August 2-7. Glow says my fertile window for this month is the 19-25 however I looked on babycenter and they said my fertile window started on the 9th which coincidentally we had sex that night and ever since I have been feeling nauseous. Could I be pregnant? And how soon can I test to find out? I have a bachelorette party coming up for a family member and want to make sure I am pregnant before I drop out since we are going to the winery.