Good luck with that one!
Sorry, seriously - we all have the same problem. For one thing Sjogren's is difficult to diagnose, and also very few GPs or other doctors seem to have heard of it. I had a whole ragbag of symptoms for ten years before getting a diagnosis, which seems to be about par for the course. In that time I consulted my GP, a dermatologist (for a skin rash), an opthalmologist for the associated dry eyes, a rheumatologist (arthritis tends to be part of it too) and a dentist. None of them put my symptoms together. In the end, it was finally my GP who relented and ordered a blood test for anti-salivary gland antibiodies, which came back strongly positive.
As a sufferer and a former nurse (who also didn't figure it out!) I can't advise you strongly enough to put aside any resentment towards your GP. Sjogren's is an auto-immune condition - i.e. one in which the body attacks its own tissues - and as such is very much affected by our mental state. Harbouring resentment is a very good way of ensuring that your condition will progress and affect more systems.
The best way to approach Sjogren's is to accept it, live with it and not get angry about it. There's no cure anyway, whatever stage it's diagnosed at, so early or late diagnosis makes no difference. Like all auto-immune conditions, it's very susceptible to spontaneous remissions, or even complete disappearance. I had ten years of misery, with dry eyes, dry mouth, arthritis, peripheral neuropathy and Reynaud's syndrome, after which my condition suddenly improved over a period of about six months, with disappearance of most of my symptoms. Six years on, I'm left with just a mildly underactive thyroid, which is effectively treated with medication, and occasional episodes of dry mouth and eyes, which never last very long.
Incidentally, Sjogren's being the weird, elusive condition it is, your blood tests might come back normal anyway... which doesn't mean you don't have it! Often the disease is only diagnosed on the basis of symptoms. Your doctor should be able to advise you on products such as mouth gels or sprays to relieve your symptoms. You can help too by cutting down on sugar - particularly in drinks, and that includes smoothies - and drinking plenty of water in small quantities at regular intervals. Drinking large amounts of water at a time washes away what little saliva you have.
Stay positive and there's every chance your symptoms will never get any worse, and may eventually clear up. Wishing you well!
Lily