I was there where you are now at similar age. Getting tired of life and hated everything a thinking that eternal rest is better. My stutter was diagnosted as severe. Many speech therapies were unsucessfull but the last one helped me. After some time I relapsed but it is still better than before. I am working on my mindset all the time and the last months I feel genuieily (how the fuck is this word spelled) happy. Sometime I feel like retarded and have these bad thoughts but it does not last longer than a day. So, it might get better but you have to work on it, be it your mental health or speech.