There are a few main points to bear in mind:
The feeling of overwhelm comes from trying to use the cognitive thinking part of your brain (the prefrontal cortex) while it is effectively incapacitated due to lack of blood-flow.
So, What's the Solution?
In the moment, the top priority is to reduce the levels of stress chemicals in your bloodstream in order to eventually bring your prefrontal cortex back online.
Now, because your brain and body don't know the difference between reality and imagination, as long as you are thinking about, or focusing on, things that make you feel bad (worried, anxious, frustrated etc.), your brain and body are going to continue to maintain the same state of emergency they would if you were in physical danger. And that means that as long as you are focusing on whatever it is you're feeling stressed or overwhelmed by, the more of those stress chemicals are being pumped into your bloodstream - and the longer your prefrontal cortex will remain offline.
As much as it feels counter-intuitive, in order to bring your prefrontal cortex back online, so that you're able to think clearly, strategize, problem-solve, and deal with the issue effectively, you need to take your focus off it! Not forever, not even for a long time - just temporarily, in order to get your brain and body back into chemical balance.
Here's How:
Note: You can use music that you love, or physical exercise, or a game - in place of the comedy video, if you like.
Keep repeating these steps until you can't find the stress or overwhelm feelings any longer.
BUT... Do Not go back to whatever it was you were stressed by - yet!
Now that you're feeling calmer, just THINK about the thing you were overwhelmed by - and notice if there are any negative feelings. If there are, repeat the steps above.
Finally, when you can think about approaching whatever it was that had you overwhelmed, without feeling stressed, you'll know that your prefrontal cortex is back online, and you are in a more empowered and productive state, to deal with it!
I will write another post on how to get rid of the "triggers" for feeling overwhelmed and stressed.
But, in the meantime, if you can't wait for that post (or if you're just interested anyway), here's more information on the subconscious triggers for stress, and how to change them:
The Board Game Version:
https://www.patreon.com/posts/changing-board-19069932