Hey man, I've dealt with stuttering all my life. The anxiety that comes with not even being able to say my name correctly and even the stomach squeezing are things we have in common. I might not understand the on and off part of it, but I do relate to the physical speech impediment. It's pretty normal for a lot of us here. The anxiety that you feel is valid, and a shared feeling among lots of others. All I can really say is see a therapist for a year or so, if you haven't already. Practice techniques like re-learning phonics, 'soft-starts' etc, they really do help when practiced in normal conversation. Otherwise, I would say just know that this does not define you. You are not your speech. Pick up a hobby that doesn't require talking. Personally (M17), I have picked up music as my language of choice, since living with a stutter I've picked up drums, guitar and few other instruments because I don't have to even worry about it while playing. I can just put on a song that I love and play it, and be good at it. That's what comforts me at the end of the day. After all day everyday of constantly feeling terrible at normal communication, I can feel good about myself when I get behind the kit because I still put work in to be good at something. Also, challenge yourself. It will never get better if you don't venture far past your comfort zone. Do something you love, maybe pick up performance. I personally have started doing local theater, I've done a few leads and it's done wonders. Hope this helped, feel free to message me if you need anything at all. I know you got some years on me, but hopefully I could be helpful.