Hi Joanna - it's possible to have many of the symptoms of Sjogrens (including dry eyes) but not actually have Sjogren's itself. There's a group of symptoms called Sicca Syndrome (I have this) which mimic some of Sjogren's. The lack of a positive blood test for Sjogren's would suggest it's possibly Sicca but you could request the lip biopsy if you want more confirmation. Be aware that with the lip biopsy there is a risk of infection/scarring and possibly increasing SFN in that area.

Here's a link which explains it better than I can:

Sjogren's Vs. Sicca Syndrome

I can recommend Systane Balance eyedrops - my optometrist prescribed them for me. I used to use Refresh Clear Eyes Plus but the Systane have more sustained lubrication (twice daily application).