Swamped with work

Did you ever swamped with work?Esepcially when you do something desktop work.For example,once a while,you get a task to check and fix someones document.But's it's really gibberish to you, so you have to check it with other relative people on and on.You want to talk with your boss that your job is really swamped but you are afraid of getting axed.But if I were you,I'm more likely to get axed for messing up rather than telling them I'm overworked.How do you think about?