Speaking infront of class, need basic advice.

Speaking infront of class, need basic advice. Hello, I'm 15M and I do have to say that in general I've been stuttering a little less this past week especially even if it's just a tiny bit I don't feel as trapped anymore I'm normal conversations. In class it's a different story, I overthink every single word even though I've said it alone and even with friends I still think I'm gonna stutter on it and its the most random words, it's mostly one word answers that are the big issue. Im not gonna change words or stick words in front of the answer since that makes it worse in the long run my therapist says. Any tips on staying calm? That all I need cuz my stutter is 95% stress related.