Pregnancy

Ok so I have a boyfriend and we have had sex on July 6 and it was unprotected and he came inside of me and I went with him to the store and got plan b one step and took it like a hour after we had sex. And I recently realized that that was my more fertile week and I would ovulate the day after so the 7th. So it kinda freaked me out I get my period July 20 or 21 around then and I’m afraid of being pregnant because of a mistake. And I have been feeling off a little and acid and tired but I’m thinking that it’s just because I’m getting my period soon and a couple of days ago I was sick with a bug puking. I’ve been having a little bit of cramps to. But I should be fine I think I also took a pregnancy test and I took to both negative but I thought mabye it’s to early to tell because I haven’t missed my period and the plan b could affect the test. But I’m so scared so I would like ur guys opinions and what u think because I’m only 18 and I would love advice please!!