Life is pretty crazy right now and it's easy to let yourself get overwhelmed. You can stop the chain from continuing by pausing and taking a deep breath. Start, but just sitting quietly and noticing your breath. Is it short and shallow? Or long and deep?
If it's short and shallow...try this:
Inhale for a count of 4, and exhale for a count of 6. Inhale through your nose and exhale with a sigh out of your mouth. Follow that for several rounds. At the end of a few minutes, you should notice that you are more calm and grounded.
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