I think I may have spasmodic dysphonia.

Welcome to the NSDA Bulletin board.

It's hard to tell from your description which kind of the two main types of SD you might have - that is, ADductor or ABductor SD. Try going to the NSDA's website at http://www.dystonia-foundation.org/nsda/ and listening to voice samples. There are more at Dr Jim Thomas' website at http://www.voicedoctor.net/therapy/dystonia.html

What would you expect at your first doctor's appointment? Ignorance most likely if it's your GP/primary care physician. Ask for a referral.

What you need to aim for is to fast-track your diagnosis if you have SD and then explore treatment options.

Try to get referred as soon as you can to a movement disorder neurologist or otolaryngologist who specialises in SD. You'll see a good list at http://www.voicedoctor.net/links/physicians.html

There is also advice there about what to expect from your first appointment:

http://www.voicedoctor.net/physician/expect.html

The main tool for a competent SD expert is their trained 'ear'. They can hear the breaks that interrupt your voicing that are so distinctive in true SD. They should also ask you about your vocal 'history' and this often gives them clues too. It's likely they will use an endoscope to examine your vocal cords while your are voicing - often they can see the spasms that are typical of laryngeal dystonia.

Good luck and let us know how you get on.