Really good point that you've made! You feel stressed because you stutter and not the other way around. I'm of the opinion that stuttering is hereditary and neurological, and what causes stress is the wrongful approach to it. Both by society in the form of social stigma and by ourselves as self-blaming or shame. I've both attended SLPs and psychotherapists, with not much "success". Then I realized stuttering couldn't be "overcome". It should rather be accepted. But when it comes to stress, it's obviously advisable to seek help from a professional. If I were you, I'd go to a psychotherapist with this. An SLP deals with the mechanical part of speech, it won't affect your stress level. Or it will even cause you stress that you have to perform and speak fluently.