missed period and plan b!?

So last period came April 29th and lasted 6 days. About a week or so after my period ended my boyfriend and I had a broken condom situation and I took a plan b the following day. 5 days after taking the plan b I got what seemed to be another period (medium flow and lasted the same amount of time that my regular periods last). My periods are always very regular and it still hasn't come yet!!!! I took a pregnancy test and it came back negative. It's driving me absolutely insane! But below the first picture is my test and what a positive result is supposed to look like