Shouldn't I Be Bitter?

Naomi has returned to her hometown of Bethlehem, but she has come back penniless and without her husband and two sons all of whom died in Moab. She believes that the Lord is against her and that she has good reason to be bitter, insisting even that the townspeople call here not 'Naomi' meaning pleasant, but 'Mara' meaning bitter. But should she bitter? Do God's people have a right to bitterness when God's providence seems to be uniformly against them?