I experience this quite often. Growing up, I was pretty extroverted, energetic, and wild. But once I noticed that I was starting to get bullied/made fun of for my stuttering problem, I became very self-conscious and refrained from speaking. When I reached middle school, my personality changed entirely. I no longer exhibited the same confidence I had when I was a child. I’m always described as being really shy, quiet, timid, and anxious. I’ve talked to only a small amount of people in college, but didn’t necessarily make any new friends. Sadly I don’t have many efficient techniques for managing my stutter... I guess the only thing I do is substitute words for other synonyms when I can’t get the word out, and try to connect all of my words together (sort of like when you sing a song) so that I don’t take any breaks, increasing the risk of stammering.