any thoughts ?????

I had sex with condom that didn't seem to break and he didn't finish either the next day I took plan b to be sure and a week after I spotted/light bleeding and in the expected time of my period I had a regular heavy flow period and now it's done and took a pregnancy test which pretty much seemed negative in the light ! I'm still stressing out if there could be a faint line that I didn't notice or something. Is it possible tho to be pregnant ?