Sounds like you need to have a long talk with your lawyer and make sure they understand your situation. Drinking after driving is a defense to DUI, but certainly doesn't help you with the hit and run. You may need some information from a doctor about your panic condition to demonstrate how what you did was not an intentional crime, but a legitimate medical issue.
Your questions absolutely need to be discussed with your attorney. It sounds like you have only been accused of DUI and H+R so far. As such, you still have the right to present a defense at trial.
The defense of having consumed alcohol after driving typically can only be used during negotiations and/or trial. You should immediately compile a list of any witnesses and phone numbers of your treating physicians and anyone who may have seen you consume alcohol and Ativan after driving. This list needs to be given to your attorney or his/her investigator.
Also, remind your attorney your intent to use the defense of having consumed alcohol after driving needs to be disclosed to the prosecutor PRIOR to your Pretrial/Omnibus hearing (See RCW 46.61.502(3)). If not properly disclosed you will be precluded from using that defense.