Gasping in the crowds

Sometimes, I do feel breathless.
For I am getting sick with the hustle and bustle life.

I ain't a smoker and I ain't an asthma patient.
Should breathless have nothing to do with me.
But, in the crowds?
Yes, it explains.

Should the oxygen enough to be supplied for every creatures that is breathing.

But, at times, still, I feel breathless in the crowds.

Crowds that overriding the oxygen.
It's a metaphor which I wanted to emphasize so much.