How much should I freak out?

My son is 11 months old and still BFed, and my husband and I have been using the pull out method. Unfortunately one night a few weeks ago he didn't make it out in time ?

I skipped my period this month and am almost due for my next one. I took two blue dye tests a week ago and they were negative besides what I assume was a faint evap line. How much should I be freaking out right now? We're so not ready for another baby!