I usually facing with this.My speech therapist said that it's normal when u're getting a speech therapy and improving ur stuttering.But honestly,I'm not sure 'bout it,coz now I'm not getting any speech therapy,but it's always happening. I'd like to help u, really,but I didn't find any solve for that... And yk,it's always happening when u're life's getting worse,like,in a period of stress. The only recommendation that I can give u,it's just eliminate stress from ur life(or get it less) And by the way,ur thoughts are really effecting on ur speech,I'd say even more than stressful conditions. Good luck bro,break ur leg,if u need something or wanna share 'bout stuttering,just let me know