This sounds like a nightmarish experience. My only advice would be to avoid speech therapy (it’s like applying a plaster to a cancerous growth) and look into diet, lifestyle changes etc. Maybe even get a brain scan. That said you’re at an age where the stutter might just be ‘growing’ with your hormones, I know someone who became a stutterer aged 18 fotally out of the blue. Honestly, go see a neurologist / someone who understands the brain ASAP.