Mate, these things happen. It's all about content, not delivery. I'm sure you've done brilliantly despite the fluency and your merits will be well deserved. To present in front of people takes courage for a fluant speaker, it just so happens that you're made of something well stronger. I work in a job that requires me to speak to new people for about 12 hours. Some days are awful for speaking but I just shake it off and focus on the work itself, not the sound of it. Be proud of your work, I'm sure you've put hours into it and that your mark will reflect on that. We're all proud of you!