To feel dejected is to feel miserable or depressed. In this poem, Hardy talks to his wife after she has passed away. He is complaining, asking her why she left without saying goodbye. He says that she gave no indication that she was going to depart soon, and that she passed away calmly and indifferent to him. He also tells her that he will never be able to see her again (gain a glimpse). The tone of the poem is of enormous sadness and grief.
