I'm glad you're still here.
I absolutely think it is not attention-seeking to tell your therapist. I would encourage it. Maybe your therapist can help you unravel the state of mind you were in at the time of your attempt and try to make a plan to prevent this from happening if you feel this way again. Your therapist's main job is to keep you safe and it will be hard for him/her to do this if they don't know this happened.
I know it will be hard to say but I think it is very important. I wish you luck and send hugs <3