What Causes Dizziness Along With Vision Blackouts And Fatigue?

I am suffering from disiness, and recently from aroung 2 years I had some areas on my eye sight I couldnt see. its totally blind. I got fatigued easily. I feel I want to sleep for long time. I am physiotherapis. some times I feel sudden action in my body I couldnt move, as if my Brain got off. I couldnt move, all my limbs became suddenly heavy. this happened spesifically after concentration in lesson or anything.