I would try to get back to the 1mg to get started and possible increase in the next few months due to the seasonal rise that's coming up. What she is experiencing is call the Pergolide Veil that sees this happening when a dosage is started or needing to increase. This product has been found to be helpful in getting the appetite back.
http://www.smartpakequine.com/apf--advanced-protection-formula-2285p.aspx
I would also join this group and get involved here. They will answer all your questions and get you set up on a properly balanced diet and talk you through it all the way. They will read test results, tell you what to tell the vet, the whole nine yards.. You'll find that you'll be doing things differently than you are right now, but better because its right on target with what she needs.
You really couldn't be in a better place than this:
http://pets.groups.yahoo.com/group/EquineCushings/
Hope this helps.....