plan B, pregnancy test

I have seen something similar. I had sex and the condom broke he managed to pull out in time. I took plan b the next day. it's been 2 weeks, I took a pregnancy test and it came out negative. I am hoping to be in the clear? Also, another question. I have a few apps that tell me my estimate ovulation and fertile days, 3 say roughly the same but 2 say other dates.