If you’ve experienced a nightmare before, you know how awful it can feel to wake up with your heart pounding out of your chest, feeling short of breath, like you can’t breathe. Whether it was a nightmare in which you’re reliving a traumatic event that happened to you, or some other kind of scary theme which leaves you rattled upon waking up, these nighttime disruptions can leave you exhausted the next day and make you start to fear going to bed.