narcolepsy
"I was diagnosed with Narcolepsy about a week ago. I started taking Nuvigil 150mgs and at first, I felt as though I could see life with clear eyes. Colors were also brighter. But then, a day or so has passed and I am completely exhausted.  I had a sleep attack at work and I didn't fall asleep, but I felt very weak and could have easily gone to sleep.  I hope this improves. I know I need to give this medicine a chance though."