I suffer from the same problem. Been stuttering since the age of 6 I think and its been been getting worse it seems (or maybe not...but it still is very bad). It is a hereditary thing for me as my father too is a stammerer though his has subsided to quite a large extent. I've been doing a lot of searching on the internet and have come across various different ways to overcome it - speech therapy being the most common one. I will mostly probably be seeing a speech therapist soon. I also came across how dopamine release in your brain (a neurochemical in your brain) can effect speech fluency. One thing I did was take up the NoFap challenge (there is a subreddit for it /NoFap - a place where users vow to abstain from masturbation addiction because of its many negative effects - one being the uncontrollable release of dopamine- something which possibly effects your speech fluency). I haven't seen much change yet (was on 55 day streak & now on 16) but I read how one user completely overcame his stammer just after 2 weeks of NoFap. Again, there may or may not be a link between the two. While there is no link as such between confidence level & stammering, it does however exacerbate the situation. Therefore doing things which can bring you mental satisfaction can help (it is infact one of the major reasons why people partake in NoFap challenge). I know the pain of not being able to communicate what you really wanna say. I know the embarrassments that I had to face in school while reading out something loud, not being able to answer questions for which I knew the answers to, not participating in group activities, bunking classes, shying away from interacting with other people and what not. College too was similar for me and I basically wasted my 3 years when I should've been having fun with friends. And now I'm at a stage where I'll have to start working. Thinking about interviews gives me nightmares really. I don't know how I'll get over it but it's going to be tough. There is no quick fix to stammering as you may know. So I guess its something we'll have to live with sadly.