Sorry to hear you had such a bad time. Maybe you could write a letter to the consultant, listing the reasons why you felt what your dad was doing helped and for her to clarify why she thought it didn't/wouldn't. You may want to let her know you felt ignored and that you left without her addressing some questions you raised.
It is the most frustrating and irritating part of having an illness/condition where you wait ages to see a "specialist" and come out annoyed. It happens all to frequently.
Your GP should get the result of your HBA1C so you could ask him/her for that