I use Ylang Ylang essential oil. It calms me.

Go out and do something active - running, cycling, swimming... treat yourself afterwards.

A melhor coisa e tomar um banho gelado.

Stop! GrammarTime. Use the first conditional (as you have already done) only when something is very likely to happen. You're talking about a theoretical situation, so use the second conditional: "If you FELT heavily stressed, what WOULD you do?"

I'd sleep.