The Double by Dostoevsky

Nowadays i am reading the Sinhalese translation of the "The Double" by Fyodor Dostoevsky. I think i am halfway finished with some difficulties.
"Goldyadkin" is the hero of the story. Goldyadkin found a person whose figure is same as himself in his office. Amazingly he is also having his own name and coming from his home town.
Sometime i thought this is "Goldyadkin"'s imagination.
Goldyadkin is trying to describe the character's of the "Goldyadkin". It is so complex as Dostoevsky 's famous quote that man is a mystery.
Frankly saying , it is very difficult to read , sometime it caused me a headache.
But i am still reading this and try to understand the Dostoevsky's standards of the mankind.