I lied to a friend who I have never lied to before

and I feel horrible. I am brutally honest with this friend. I figure lay it all out there either they will stay my friend or run away. I lied to protect myself - I am not using that as an excuse - but I guess I am. How much does a "friend" need to know. Ugh! It is haunting me. I think I might have to text said friend. I don't want too, because then I am letting them into a very private - teeny, tiny part of my life that I use only for me.