What is causing hamlet to criticize himself harshly at the end of act 2

Left alone on stage, Hamlet muses about the strangeness of his situation. He asks himself, “How can this player be so filled with grief and rage over Priam and Hecuba, imaginary figures whom he doesn’t even know, while I, who have every reason to rage and grieve and seek bloody revenge, am weak, uncertain, and incapable of action?” He curses himself and his indecisiveness before cursing his murderous uncle in a rage. Having regained composure, Hamlet announces his plan to make sure that the ghost of his father is genuine – that the apparition was not some evil spirit sent to lure his soul to damnation.