Did your symptoms change after you started taking the Cymbalta? I noticed that you listed poor memory, fatigue, weakness, depersonalization (feeling like you can or are moving arms while driving), feeling like you have to think about speaking or moving (confusion). Are you having symptoms since starting the Cymbalta, such as sweating, rapid or uneven heartbeat, muscle rigidity (especially in the legs-cramping or burning in legs or staggering walk)? Cymbalta is in a class of medications called SNRI's. This means that it is a serotonin/nor-epinephrine re-uptake inhibitor. I was put on an SNRI, also after a 20 minute conversation with my doctor. Very shortly I began having symptoms that gradually (a period of a few months) came to a crisis point. I found that I could not remember anything. I could be driving down the street and have no idea where I was going to when I started out. I could stand next to the stove while cooking with a pan lighting on fire, but couldn't connect that I was cooking and the sound was dinner getting torched. I felt like I was a "floating head" while driving. It was the same as what you experienced. These are very possible side effects of this medication. It will be important to think about when the symptoms started to make sure. A word of caution, if you think that the Cymbalta is causing some of your problems, it is very important that you do not stop taking it. This may sound counter-intuitive, but this type of medication has to be tapered of in dosage under the supervision of a doctor. This is not meant to scare you, but your symptoms could be made worse by stopping cold turkey. My doctor basically stopped me cold turkey, and I suffered as a result.
I have had dizzy spells for years, and I was diagnosed with Meniere's Disease. It is a disease/disorder which affects the nerves inside the ear. An ear specialist can perform the tests necessary to determine if this is the case for you. After being taken off of the SNRI, I started seeing a new doctor who ran in-depth testing of my hormones, vitamins, and mineral balance. She also tested my neurotransmitter levels. There are 4 neurotransmitters that I produce in minimal quantities, two of them are serotonin and nor-epinephrine! This is why I did not respond well to an SNRI. If there isn't enough to "re-uptake", it will not help. After learning that I have neurotransmitter and hormone imbalances, I started treatment and researched my condition. Some neurotransmitters influence muscle tension, and if you have too much or too little of an NT, you can have muscles that are in a constant state of flex. This can be painful. Certain hormones regulate your energy levels. Cortisol is a big one for that. If you don't produce enough in the morning, you may find that you can barely crawl out of bed. It may be a good idea to try to find a doctor who will perform hormone and neurotransmitter testing. It's definitely a good idea if you believe that you are developing symptoms that are making you worse since taking Cymbalta. Remember, do not stop taking it on your own. Consult a doctor for instructions to lower the dose if you decide to stop taking it so that you don't suffer the side effects of quitting cold turkey. Make a list of symptoms and concerns, and when they started to take with you to your doctor appointment. I hope you find some relief soon!
You definitely need a new neurologist. ADD is present in childhood, and does not start in adulthood. It is also inappropriate for a doctor who is not trained in psychiatric conditions to make such a diagnosis of extreme depression in 20 minutes. In reality, I'll bet he's too embarrassed to admit he doesn't know what's wrong with you.
There are a number of conditions that can cause such neurological symptoms Have you had an MRI of your brain and neck? You don't mention how long this has been going on, but you do mention you are positive for mono. Mono can be brutal (I had a bad case..took several momths before I could get through an 8 hour day at work and nearly a year to recover).
If your doctors don't think you have an active mono infection, another possibility is neurologic Lyme Disease. You could request blood tests for Lyme. One problem is, though, is that many people who are very sick with Lyme test negative. The CDC says this shouldn't exclude it, but many doctors don't know the disease well enough and rely on the imperfect tests. Have you been bit by a tick or did you have a red rash before the symptoms started? Usually with Lyme, there are other symptoms, but not always.
You can look at the symptom list in this document and see if you think it might be possible. http://www.ilads.org/lyme_disease/B_guidelines_12_17_08.pdf
I believe there is also a Post Concussion Syndrome that you might want to research. Another good reason for an MRI...