Same here dude . My stammering got worse after my school as i have to face the real world .. i always wanted to study abroad so i gave the ILETS examination 4 times and guess what i scored 7 + bands in reading listening and writing but got only 4 in speaking even with the stammering certificate. I was so ashamed that I couldn’t show my result to other and that part was turning point i isolated myself in my room no connection with friends no relationships and i barely speak to my family . This habit led me to consume drugs as it helps me to escape the reality .i know it sounds stupid but thats the only thing that is saving me from committing a s#icide ..guys it feels so bad when you know that u have the capability to do better than others but ur stammering keeps pulling you back ..you are not alone dude .