At a office party, I tried to invite a female coworker for a drink. She rejected me in front of everybody. I felt bad.
Ah, that's rough. That was a very bold move on your part. But sometimes fortune favors the bold, as they say. I think you'll be happy later on not having to wonder "what if." Still though, she could have maybe been more discrete about things.
She has been mean and making sure that everyone knows. That is the thing.
Ah, I see. Well, it's a good thing you were rejected thing, maybe. At least now you know what kind of a bullet you dodged. Plus, this is just another step in your overall confidence and character building. The next time you ask someone else out, it will be easier.