Sudden increase in floaters, flashes of light, or a "curtain" or shadow coming across your vision.
UPDATE: I have a migraine now so I'm really thinking it was an aura. I asked some people in a group and they described their auras in the same way.. I am going to call my Neuro in the morning but just in case it wasn't an aura and I do have a retinal tear or something, what should I watch out for?