Oh dear.
From the little you have said here, you sound like you have a psychogenic voice disorder (no doubt exacerbated by some sort of organic ie physical condition.
I think you need to see a salt who specialises in voice disorders asap.Have you asked the GP to refer you? You need to see a specialist in this particular field (its not mine unfortunately) Are you in London? I did my voice training under a salt called Clare Morris who was fantastic. She also used hypnosis to treat these problems. We had some fascinating case histories (eg a woman who lost her voice after a very bitter divorce. Amongst other treatment methods she was taught under hypnosis to visualise him as a huge weed growing in a beautiful garden and to uproot him.)
It would be worth phoning the department at City University (where Clare was/is based) and asking for assistance.
Also, cotact the Royal College of Speech and Lang. Therapists, who should be able to put you in the right direction.
If there is a waiting list, it may be worth going private. The SALT website has a link to one for independent therapists. Look through their specialisms/interests and find someone who specialises in voice disorders. (Make sure their list of specialisms isn't too long-noone can know it all.)
If you are not in London, find out from the Royal College which is the nearest uni to you with a SALT course, then ring them and ask for a recommendation.
Get back to me, if you need more help. As I said, it's not my field (that's S/N and augment./alt. communication) but I know how you should go about seeking the right salt for your needs.
Oh-and stop worrying about your pupils. At the moment, your prime rsponsibility is to yourself. Worrying will only make things worse, and keep you away for longer.
If it is any consolation, voice problems are vvvv common in teachers (whether psychogenic or organic in origin.)
Don't panic. You will be able to sort this out!!
Let me know what happens.
XXX