I'm so sorry you were in a place where an attempt felt like the only option. I hope you are able to talk to your T about it so they can help you process through it. Even though you feel safe now, I think it's still extremely important to tell your T, because then if you ever feel this way in the future again, hopefully your T will have helped you come up with a plan for safety. Though I hope that you never have to go through this again
I like LonesomeTonight's idea of what to text your T