I agree with both Weny-Lee and Vinnie.  LISTEN to your body.  Those of us with CAH can hurt much more severely when our bodies are not equipped --pharmacologically speaking. 

I have found that ER doctors are of NO use whatsoever when it comes to CAH-related questions.  Only your endo  can provide helpful info.  Call him/her right away to get an educated opinion.  But I have found that the older I get (now over 40, ugh), the more I need to be proactive in terms of my meds.

Hope this helps -- Best, Eric