Hi Roxann, I understand very well how confusing this all is. Sometimes it takes a few years to let our bodies tell us in more clear ways what we are suffering from.
My story is kind of like yours. I was diagnosed with FM a couple years ago. The symptoms all matched up and treatment was moving along OK. My rheumatic blood tests were negative. Over the next year I started getting swollen toes, like red sausages, and lots of foot joint pain in the same places on both feet. Still negative blood tests, but an orthopaedic dr said I could have early RA and started NSAID treatment with success.
Then the NSAID stopped helping much and the sausage toes came back, along with hand joint pain, redness and swelling, the same on both hands and both feet. These specific joints on me are the typical RA joints. (I also have some OA in typical OA joints.)
I have yet to test positive for RA, but some were high-normal and my anti-ccp was elevated from last time. So I am like you in not showing inflammation in my blood but definitely on my body...Doc says it's RA and will start MTX.
I'd say the way I feel lately is much worse than a couple years ago. My fatigue is huge and I hardly do anything without paying dearly in fatigue and pain the next day or more. My knuckles are large and boney looking, my pinkies are sticking out and up too. Really weird. It hurts to do normal things in the kitchen or bathroom. Knees are beginning to be trouble daily too.
So, to summarize, if your body is like mine, you will start to know for sure. However, as you know, some people have very little symptoms and yet have RA damage happening! OA can be very painful too, of course. I did a lot of reading about OA and RA online. I found out which joints are usually affected by each, and how both sides of the body are usually affected by RA.
My understanding is that about 20 percent of RA patients don't show positive blood tests. Online you will find lists of criteria that doctors use to diagnose RA. A patient must have a certain number of these findings to receive the diagnosis. These include visible/palpable joint changes, image tests like xrays or mri's, stiffness for more than 30 mins in the morning, joint fluid tests, etc. as well as blood test results. (You might also show your doc phone pics of your worst days of swelling.)
I sympathize with your worries about not getting treatment before damage is done. Then again, I wouldn't want to get treated for something I didn't have! I hope the Cymbalta improves your symptoms soon. Be patient with the whole process, and keep being pleasant with your doctor if you can...LOL! I hope some others chime in with their thoughts too.