Help with clear blue.....

okay, hi. I use only condoms with my boyfriend, but it broke before he came and he panicked and pulled out. I took Plan B two days later and the following week, I had three days of gross, dark brown discharge that was almost as heavy as my period, but not painful. It's been three weeks since the incident so I took a clear blue test and the digital said I'm not pregnant....but I barely peed on it (the first one didn't work and I used all my pee...tmi....so I only got a few drops/a trickle on the second one)! How much do you have to pee on a clear blue stick? Is it inaccurate? :( did I have to pee a lot?