How to let your school help you with sadness and self-harm?

I've been depressed and now really numb... My english teacher has seen my cry and lets me go outside, and last week wanted to have a word with me after class but I said was fine and she was like OK. Then, she comes to me in lunch time saying if there is anything I can do let me know and made me go to my head of year because i wrote my creative story on depression and how i wanted to kill myself. My latin teacher also said she was always free for a chit-chat because she said I didn't seem to be a very happy person. I sort of regret being resistant to her help now. I don't want to have to ask for an appointment for school counsellor, but I think I now do want help. How, can I get my teachers to help me, and sign to her I'm in need with it with my self-harming issues.