You are not a failure. You are not your stuttering. Think of it like this. You have such a severe stuttering and you ave fought it for so long. That means you have a ton of experience for living and surviving. I believe in you. Spmetimes it helps to laugh like crazy about how bad things are. Sometimes it helps to talk to a person about how bad things are. In such a session you are not alllowed to make solutions. You only talk about the bad stuff and how much life sucks. At some point you will be empty. Then you will feel better. Also write a journal and unload.