Distorted vision in right eye suddenly?

I was watching tv last night and I thought the tv was going blurry but found it was my right eye.... its hard to explain but my perifrials darkened and it was blurry especially when I looked at my phone and i got a headache right after.. I went to bed and still have the headache but my vision cleared up... could this be an allergic reaction to msg or hard shell fish in the chinese food I ate an hour before?.. or could it a concussion since I am a boxer but havnt recently got hit in the head hard?.. why would it just randomly start like it did?