I wish I knew the answer. I have the same problem. I am nearly perfectly fluent for a year or two then I have a "relapse" thats starts really slow, just a bit more stuttering. This makes me a little anxious because I never know when it will strike. Of course it happens again and I get more and more anxious until its happening so much and I know I have lost control. Every time I have to speak I get this awful knot in my stomach and I can hear my heart beat. I try to stop it, which results in severe blocking and pauses. I start having nightmares- the same ones over and over- in the course of about 2 weeks my speech completely deteriorates and I feel like I have an elephant on my chest all day. Like last night I dreamed someone had cut off my head and I had to put it back and repair everything in there myself- my spine, my trachea and esophagus, my vocal cords and all the neck muscles. People who I recently met or became friends with notice that I am stuttering a lot and wonder what the hell? Then I can't live like that anymore so I isolate myself. Then I get fed up of that and just go out and live my best life- or develop more ingenious crutches. And then my speech starts to improve again, and before I know it, I am fluent again for the most part and comfortable. The speech anxiety abates mostly and I get back into the rhythm of things with fluent speech. Of course then it happens again after a year or two and then rinse repeat. Its bloody exhausting. Each session of stuttering lasts about 1-4 months. Getting shorter as I grow older because I think maybe I am learning to get out of the anxiety faster. I really don't know.