She better get it together if she ever wants to get a promotion andor better job

Maybe co-worker worked extra hard the previous day and finished everything she had to do? Just because someone is having a slow day doesn't mean all their days are like that.

Cry me a river, sounds like you need a life.

what could the assignment be? This is really funny

Don't compare yourself to others. If your coworker actually never works it will eventually show.

Don't worry about it. Your coworker isn't working hard and you are. It may not seem like it now but your work and her lack of work will pay off in the end.

What is this assignment that you've toiled so long on?!

If you ever get a break, use it to craft a paper knife and take a picture of yourself poised with said knife over said coworker's head

See op, you're just the company workhorse, a asset, but expendable. She is a innovator working to solve world hunger.

Sounds like your efforts weren't as fruitful as your co-worker's.