If I were in your shoes I would call my neuro immediately and try to speak with him/her and if they're not available then I would ask for a nurse. If neither are available I would say "screw it" and head to the hospital.
When my neuro diagnosed me I asked him, "Is there anything that I should pay attention to or seek immediate treatment for if it happens?" Among all the obvious he also said that if I see a grey spot in my central vision line (I guess wherever I'm looking, if I see grey rather than the object) then I should go to the ER immediately. He said the longer it persists the more damage to my eye sight.
October 29, 2009 - Dx with RRMS
June 22, 2010 - Dx's changed to Devic's (NMO)
January 4, 2011 - Dx w/Syringomyelia T4-T9, Migraines, and Possible MS (again - long story)