Hi @Cinnamon_Llama
This sounds like a difficult situation to be in. The fear of having to tell your family is normal, I've been there.
I agree with a suggestion catlover101 has mentioned about writng a letter to your dad. It can help express your emotions but also help you get out what you want to say without needing to answer questions write away. Even if you place it somewhere he would see everyday, in his sock draw or something.
I see that your worried about revealing your identity to the person on kids helpline, would it be helpful to have the discussion with her that, you've used a different name and explain why or just even say for privacy reasons. That way if the 3 way call is something your interested in or even if she speaks to your dad for you, there is no mix up with names and she might not mention that either.
You have mentioned that while telling your family is scary is there a friend or someone you have mentioned this in the past who could potentially be there to support you with the conversation with your dad. They might be able to just have a presences there that can take some of the pressure off.
Wishing you all the best and there is always this space and community for more
