Your description of the pain in the eye feeling as though it is coming from the back of your eye is consistent with the pain I feel from occipital neuralgia(ON). I suffer from TN and ON and I get eye pain from both conditions but its different with each condition. You really need to see a neurologist to sort it out although it does sound like your regular doctor is doing the right things. A TN diagnosis is scarry and I went through denial as well. I think everyone who posts about the condition does too. Its known to be the worst pain that afflicts humans so I probably don't need to say more. Check out the "Stickies" at the top of thread. There is a lot of information in there and some good links to get you more information. The book named Striking Back which is sold through the TNA is an excellent source of information about TN. You may want to consider it.

Try to stay calm until your doctor has the results of the scans and until you know just what you are dealing with. Its easier said than done, I know. Take care!