I really didn't want to say anything, but

Seriously, today is too much, I have to go talk about this. While I've been working every day for 3 weeks, the same coworker only worked like 3 days and acted like they did everything. I went to pick up mail today because they told me to, and it was the same stuff I left behind last time because it was too heavy? I'm so mad they're bragging about their work when they barely did anything.