Sometimes lesions can be the blame for your symptoms and sometimes lesions that are seen can not.
Have you seen a Neuro-Ophthalmologist yet? If not, have your primary refer you to one. They can do OCT and vision field testing as well as other tests. Be prepared the appointment is approximately 3 hours long for the initial visit as well as have a person drive you to and from the office (as they dilate your pupils).
Considering that you have an old and new lesion in a different area, proves dissemination in time (I believe).
Have you checked out our forum's health pages? If not ,there's a plethora of information there!
Here's the link: http://www.medhelp.org/health_pages/list?cid=36
I'm sorry you're going through the symptoms you're experiencing. Lord knows we all feel or have felt some or all of your disheartening symptoms.
It would be hard for us to guess what your Neurologist would say, but we would be definitely anxious to hear the verdict when he comes back from his/her vacation!
Please keep us informed!!