RA Factor high with Sjogren's?

I've been sick for 1 1/4yrs.at least. Have arthritis but rhuemy says it's not RA. Last year my RA Factor was 79.5 and then went to 54-24-76. Few months later (last week), it was 140. Don't understand what it means. I keep getting very dry mouth and sometimes dry eyes. Then I get better. It's off and on. Recently my mouth is somewhat dry and it takes more of an effort for me to breath easy. I have some asthma but my allergest says it's not asthma. I agree becuase I can tell the difference.
1) Can Sjogren's cause an elevated RA Factor?
2) Does Sjogren's come one gradually or would I have known by now if I have it? (My anti-Smith tests came out negative last year and last week).
3) Can Sjogren's cause neurological disturbances? (i've been having pins/needles and seizures that don't show up on an EEG.
4)My skin peels on my fingers/hands and feet. My hands and feet get freezing.

I'm always thirsty.

Need help. Thanks.