ltfh4

I last had sex on the 20th. We used a condom at first and then we started not too, but there wasn't really any penetration. Before anything happened he turned completely away from me and then ejaculated. There was no pre-c** before that and he went to the bathroom before I got there which would have most likely killed any sperm that would have been in his pre-c**. I was still very nervous and was already a week late, probably because I exercise a lot am an involved in a sport right now, but the stress was killing me so I told my parents. I took a pregnancy test on the 22nd and took the Plan B pills somewhere around 48 hours. I am still stressing out about it and am wondering when I should be getting my period if I was supposed to have it now or last week to begin with. Can stress even if you take Plan B make you late?