I can definitely relate. I just gave my second talk last night. I've been sober just over 14 months and wasn't asked to speak until I reached one year. I get the same buildup of anxiety, worrying I'll run out of things to say before the time is up, worrying my mind will go completely blank and I'll just stand there like a deer in the headlights, etc. Another member of my group told me we all suffer from that, especially at first. Last night I joked that, while that may be true, I've yet to see anyone pass out or throw up during their talk, but "the night's still young, so stick around!"
It went well, though. I think the key is to pray about it, keep focused on the reason you are giving your talk, which is to help the still sick and suffering alcoholic, or to maybe say something that touches someone who has substantial sober time but is struggling with something similar. I heard from several people after my talk that something I said made that kind of impact. In other words, remember that even though our talk is an account of our personal experiences, ultimately it isn't really about us.