Can she use texts against me?

I have court in a few weeks about getting joint custody of my son. His mother constantly provoked me through texts and voice mails to the point where i would text back and argue with her. She is claiming that a few days ago, on the way to a child support mediator, i threatened her life, told her i was gonna get someone to whoop her ***, and grabbed the steering wheel and jerked her off the road. I did none of the above. I did yell and scream after she started with me. Then she left me at a store 30 miles from my house. I dont blame her. But she says she is going to use our angry text conversations in court to show i am mentally unstable when all i was saying was i wanted time with my son and she refused.