I lost my mojo, how can I get it back?

You have to work your way up slowly. You should probably get comfortable speaking in front of a crowd first. You should first start out with about 10 people. Then slowly work your way up until it doesn't matter how many people are there. Just get comfortable talking to numerous people. Don't be afraid to make mistakes. Just pretend you're having a normal conversation with someone. Only you're the one talking. If you stumble upon something, laugh at it or just don't make a big deal out of it, then move right on.