What you are describing is extremely common. Almost universal, I would venture to say.
Applicable rule from The House of God (essential reading, by the way):
3. AT A CARDIAC ARREST, THE FIRST PROCEDURE IS TO TAKE YOUR OWN PULSE.
I dismissed that as a joke when I first read it (before I was a paramedic). Now I see the genius, and I honestly remind myself of that phrase whenever I feel things starting to get out of control.
I would advise you to always remember:
-Our job is simple, and often becomes more so as the "crazyness" of a call increases.
-Do the same things on every call ALL of the time. Even the BS ones. Cannot stress this enough.
-Reassess mental status, check lung sounds and vital signs often.
-IV, monitor, O2. If you find yourself "stuck" on a call, give yourself time to regroup by reassessing or doing one of those tasks.
-For the VAST, VAST majority of the time (read: pretty much all of the time), seconds do not count. Take your time to do things right and relax. You'll get things done quicker than if you had tried to rush. This is why we walk onto the scene and do not run. Carry that mindset with you for the rest of the call as well.
-Embrace the phrase "it is not my emergency," not out of callousness, but out out of respect for a job well done. On a scene where everyone is freaking out, it is your responsibility to calm things down-- even if only by example.
-Don't be afraid of mistakes. Be very afraid of repeating mistakes.
-Always remember that we are here to provide comfort and reduce suffering, and are placed in a position of trust that enables us to do so.
Some of that may be helpful and some not. Just some lessons I've learned along the way and would like to pass on... Things will get much better with time and experience, but don't expect it to happen overnight. Good luck!