The title suggests a fresh start, but the poem opens with dressing for a funeral. On the first day of the rest of his life, the speaker puts on a new black suit. The word "new" matters: this is a beginning, but one that starts in grief.
What he mourns is unusual. He isn't grieving a person, at least not directly, but the "storms that have driven me," along with "invitations to wonder." These sound like turbulent, exciting forces that once pushed him forward and opened the world up. Now they seem gone. The last two lines, "the great wound / I did not hope to save," are the hardest to read. The speaker seems to accept a deep hurt without trying to heal or rescue it.
The mood is quiet, solemn and resigned. Nothing is shouted. The short lines and plain, formal tone make the loss feel settled, as if the speaker has already stopped fighting it.