Hi Deana and welcome to the group!
I am surprised that you have been given a clear diagnosis but not been put on any medication. Obviously waiting for an appointment for that long, and you're still having the same symptoms, is not feasable.
I would got back to your GP and tell him that although you have been diagnosed with IIH (he should have a letter from the hospital telling him this), your symptoms are the same and you have not been prescribed anything to help them, and that you know that Diamox is usually given to patients with IIH, to treat these symtoms. Make him aware that although you do have an appointment for the end of January, you are concerned that you are having these symptoms still and are finding it difficult to cope with them. Ask him if he could prescribe something in the meantime or at least get your appointment with the Neuro-ophthalmologist brought forward.
Hopefully he will be able to one of those things for you. Keep us updated.