The Problem (and solution) With Good Time Management Skills
There is a problem with good time management: being efficient allows time for more tasks that add even more stress. Indeed, you might notice that the more you're able to accomplish, the more people will expect from you. The answer is not to slow down so you don't get this work, but to prioritize what you have.
When you’re feeling overwhelmed, be honest with yourself — and others — about what you can accomplish. Then, evaluate things in terms of priorities, not time. For example, when your manager requests you take on a new project, answering with "I don't have time for that" may seem abrupt. Instead, ask: "Where would you like me to prioritize this against x, y, and z?" Asking for this guidance does two things. First, it reminds them that your time is limited. Second, it places the responsibility on them to tell you which task is more important and help you avoid missing a critical deadline.