How do you stay calm when everything feels due at the same time?

I feel like I'm stuck and stressed all the time these days, I study at night and work during the day, but my brain feels full. I'm terrified I'll fail since deadlines keep arriving. I attempt for maintaining focused, but tension quickly takes control. I sometimes consider about requesting someone else to take my PMP exam for me since I feel so stressed. Has anyone else gone through this? How did you handle the stress and keep going?