This can only from person to person, and symptom to symptom. As Catherine Iceton showed in the BBC documentary, she recovered her energy within a few hours. She had various other symptoms, which took longer to recover. Similarly, a young lady presented with paralysis of both legs; she became much more outgoing and cheerful within a few days of beginning treatment, but the paralysis took nine months of treatment for the first leg, and it was 12 months of commencing treatment before she could walk without crutches again.
So: keep a symptoms diary, so you can see if you are getting better. Get your friends and carers to tell you what has changed, that they can see, but maybe you can't (for example: your energy levels, your mood swings, how cheerful you are). When you talk to your doctor, take your symptoms diary with you.