The only thing that I can say is that you are not alone. My only advice is to try to keep busy and try not to focus on it. (I know, I know, very hard to do). Best to you. YOU have to take charge and BEAT IT!
Yes,that floating feeling...the feeling like you are in a dream-state. Yes, it is anxiety-related. I get that often when I am in a stressful situation....and sometimes an exciting happy one too! It is a shame but sometimes that anxious and that exciting feeling trigger the same responses.
I am so sorry for your terrible loss. DId you bring her home with a clean bill of health? If you did, then it sounds like a terrible oversight by the doctor.
I cannot begin to express my sympathy for her passing. Just remember she is in God's hands and remember the blessing you had by being able to hold her in your arms. My prayers are with you.