Speaking in public is a skill, just like any other. And the way you improve any skill is to practice.
I highly recommend
Toastmasters as a way to practice your speaking skills. I've been doing it for six years now, and because I've practiced so much in Toastmasters, there are very few public speaking scenarios that can bother me. Getting called on to deliver a keynote presentation in thirty minutes is one... that still brings chills.
But a general 5-7 minute presentation... no problem. And when things pop up like typos, missed words, and so on, you're more comfortable and can go with the flow.
For reference, I prefer to memorize stories, rather than words. A five to seven minute speech should have about three stories in it, or perhaps two. My notes, and I do use them, list the story itself, and not the actual words. As long as I know the concept I want to convey, I can run with it.
I routinely deliver 45-50 minute presentations to technical audiences, and I enjoy it, much like Epona and others. It's great to be on-stage and the center of attention, even when I flub up. I find the conversational approach (having a discussion with a couple of people in the audience, while everyone else listens in) to be the most effective.
Good luck for the next one!