I recently posted a video with a breath metronome built into it to my youtube page. Viewers are supposed to breathe along with the rising and falling bar to help them pace their breathing. It will guide you to breathe more slowly, at a rate of five breaths per minute. This reduces the extent to which you hyperventilate and will help you engage the diaphragm with every breath. It feels awkward and even uncomfortable at first, but it will reteach you how to breath peacefully. You can access it here:
I hope that you find that after 5 minutes of breathing at this rate you feel relaxed, calm, and confident. Check out the various self-care exercises to pair with paced breathing found on the site. You might start with the breathing chapter that can be found here: