What's the thing that makes you wake up after fainting?

Question

Today at the doctor's office, I had to get blood drawn. Throughout the procedure, I was very uncomfortable and felt some pain, but afterwards, I started feeling dizzy and my hands went numb. I passed out and only saw faint images, such as the nurse's blurry face. Then I heard the faint noise of cracking and I smelled something that made me automatically shoot upright and cough. I have no clue what it was, but it smelled like Vicks Vapo-rub. It was the thing that made the clicky noise.

What the heck is that thing and how did it make me wake up so quick?

Answer 1

It could have been ammonia. That has a really foul smell enough to put tears in your eyes.

Answer 2

smelling salts...amonia