Please find a therapist or start speaking to your school counselor. Self harm, like punching yourself, is a very dangerous coping mechanism. They will help guide you into a better mental state and 100% your speech will improve just by learning knew ways to cope with frustration and anger. Therapy is beneficial for everyone everywhere — for your sake, seek one out. There are free options if you or your family can’t afford one. If it’s a concern and you’re in the US, there are laws in place that the therapist can’t share anything with your parents, if that might be a concern (outside of a few danger to yourself exceptions). I wish you the best!