Heightened anxiety and adrenaline can cause surges in dopamine, which can further exacerbate speech blocks and dysfluency, especially in stressful speaking situations such as meetings/presentations etc… If you get your anxiety under control it’ll help a lot. You could take a beta blocker to “tame down” the adrenaline in those situations. Lots of solutions for controlling anxiety. Just depends what you feel comfortable taking. I take Prozac. Others take Sertraline or Lexapro etc… many options. Talk to your Doctor. There are supplements which can help too, such as L-Theanine, Magnesium Glycinate and B1/B6 etc…