Last semester, one of my classmates showed me a GIF that is supposed to help stop your anxiety. What you do is you look at the GIF and breathe along with it and it will help calm you down.
It’s a very simple idea but it seems to work well as I have seen it posted around a good few times. I think interactive elements like these would work well with my app and would be more effective for breathing exercises etc instead of just reading text.
The site – http://www.duffthepsych.com/stopanxiety/ – also gives you background music (another element I think my app needs) and a few paragraphs that help you realise that we can beat anxiety and we will be ok, as well as focusing on your breathing.