Hi there Worriedmum99
Welcome So true, it wasn't meant to be like this was it , I'm glad you found us and feel less alone. Parents often feel like you do as you'll see on the threads, we arrive feeling completely out of our depth.
It takes time to learn and practice the tools and from the lessons, small gentle steps help the journey. I found it helpful to practice one tool at a time and then move on. I often think to myself learning the skills is the greatest gift I can give my 28DD. My 28DD has completed 12months DBT and she uses some of the tools too

What books have you read? My favourite go to is
Loving Someone with Borderline Personality Disorder it provides solid tools and very detailed explanations of how to use them.
WDx