Plan B effectiveness for overweight women

Omg i'm freaking out. My boyfriend and I were having sex yesterday and the condom broke. As soon as he noticed we ran to the store to get Plan B. I was calm because I have heard the effectiveness was good for it and many of my friends I know have had similar scares and been fine. I started researching when I got home tonight and saw it says women over 165lbs can't use and will not work. I'm freaking out right now , because I weigh about 200 and worried I'm  going to be pregnant. what is the likely hood this is actually true and what other options can I do to limit pregnancy ?!