I completely know what you're going through. I can't verbalize my feelings either, except to say "I'm severely depressed." but when they ask "are you having suicidal thoughts?" I lie and say no. Every time. So I've been successfully hiding my feelings too. So know you are absolutely not alone in that.
Your best option is to show someone you trust your scars ( a parent, maybe, or a teacher or a close friend or a religious leader?) and tell them you need help. That's all you really need to say to get ahold of someone professional who understands your problems. Or go to an ER and tell them you're cutting, they might be able to help you if you feel your problem is an emergency. There are evidently a lot of cheaper community clinics that you may be able to go to for your self harm and depression, you may want to check something like that out.
And know you are not alone. :hug: Feel free to PM me if you need to talk.