Heres a breathing technique my case worker showed me in the ER when I couldn't breath and was starting to pass out. Breath in through your nose. Breathe out a longer breath through your mouth. Focus on an object while doing this. Make your out breath longer than your in breath and just taper it out. This kept me from hyperventilating when I was having a psychotic panic attack. It works, it really does. Also keep telling yourself that you are safe.