Leos don't lack confidence, do they? You may need work...No one would ever accuse Leo of being a pushover. Quite the opposite. Your Fixed Sign means you can't be pushed at all, unless it's something you want to do anyway.
You have no problem being assertive in the workplace, which is fine up to a point. Just take care that it doesn't turn into impatience or aggression.
A little roaring goes a long way at the office! Anyone who knows you will assign the repetitive tasks to someone else and let you make the presentations to the higher-ups. That's where you'll shine!