Don't freak out about that, but take it as a way to measure how you're doing. When you hit a communication snafu, be careful not to rush to judgment about either yourself or your daughter. By nature she wants to have a relationship with you, but often gets herself into situations where she doesn't know how to proceed. Your steady hand on the tiller makes navigating these times the way you build open lines of communication. Last, take her to a new location to speak.
Kids open up when they're away from the sources of their trouble.
For many kids that means home. Take her away to talk, and watch what happens. Writing things down really does help. By the way, all these suggestions work. Summer and I are buddies again, though I doubt I'll be on her email list anytime soon.