When can I test to see if I'm pregnant?

Okay so my last period was April 4th- 8th and my fertile days according to eve was April 18th-21st or the 24th I can't remember which..but anyway we had sex on the 19th, 20th and 21st and even before my fertile week... I am a week late of a 28 day cycle. Because I was previously on bc (pills) and stopped it before I started my last period...idk if that affects it. When's the soonest I can find out with a pregnancy test that I'm pregnant? And telling symptoms? I've felt sick for the past week every time I eat or smell food, and I pee a lot more than usual!