In need of help. Sleep beneficial?

I am a 17 years old girl,currently schooling and my major exams are in October.I have self harmed since I was 14 years old.My school counselor spoke to me but eventually the sessions stop when I was 15.Subsequently there was no follow-up session,as school exams are nearing,everything feels overwhelming to a point that sometimes the thought of self harm comes back,I don't wish to speak to my family members and friends as their first sentence after I told them I self harm would be:Why did you do such things are you not getting what you wanted? I feel that they do not understand what I am going through and as for my Teachers,I will wear a jacket to cover up the scars so that they do not know.I feel that going to a psychiatrist or psychologist will not be useful at all hence I am looking for other alternatives.Does keeping a personal Journal to pen down your thoughts everyday before sleep beneficial? All the thoughts in my head,is there a way to clear them as I need to focus on my studies