It’s pretty common for people going through stressful periods to have panic attacks just as they fall asleep or even during sleep, after having managed anxiety successfully during the day. This is because our psychological defenses and coping strategies drop away as we fall asleep, leaving anxiety symptoms free to rise. This can result in anxiety dreams or even panic that wakes you up.
While there is no way to “erase” anxiety, allowing yourself to experience the anxiety in a safe, mindful way during waking hours can help to minimize bedtime panic attacks and allow you to sleep better.
Specifically: allowing yourself to feel the anxiety until it passes, while–for example–talking to a trusted friend or your therapist, journaling, or just crying, can be a relief.
Moderate cardio exercise can also help in that it uses up excess cortisol, which triggers panic attacks. (However, don’t exercise right before bedtime as that may wake up your system and lead to insomnia.)