As I was reading the poem, I felt a deep sense of sadness and regret in the writers choice of words. It was as if he was writing while reminiscing about the better life he had before where problems were small and Life itself was simple. He was regretting what has become of his life and has expressed a desire to go back to that simple life. The choice of words create images of making hard choices, doing things not on ones own will and of deep sadness of what has become of ones life.
Now I would interpret the poem per line based on the connotation that I got from them. The lines Into my head rose the nothings, my life day after day connoted that he was reminiscing and memories of his life before were coming back into his mind. The next lines But I am leaving the shore in my skin boat is that he had to leave the life he had been used to.
The next lines it came to me that I was in danger may be pertaining to the grave reason that he had to decide to leave even if he does not want to or a big decision he had to make. The next lines and now the small troubles look big and the ache that comes from the things I have to do every day, big may mean that now that he had decided or left, things will not be as simple as they were before because every decision have consequences and thus involves certain responsibilities and risks that we have to take.
The next lines But only one thing is great only one. This, in the hut by the path to see the day coming out of its mother and the light filling the world means that the writer still yearns to go back to his simple life before, where everything he wanted was to see the sunrise in the morning in his humble home.