In what way is Ona falling to pieces?

From the text;

"Ona, too, was falling into a habit of silence--Ona, who had once gone about singing like a bird. She was sick and miserable, and often she would barely have strength enough to drag herself home. And there they would eat what they had to eat, and afterward, because there was only their misery to talk of, they would crawl into bed and fall into a stupor and never stir until it was time to get up again, and dress by candlelight, and go back to the machines. They were so numbed that they did not even suffer much from hunger, now; only the children continued to fret when the food ran short."

"Ona was visibly going to pieces. In the first place she was developing a cough, like the one that had killed old Dede Antanas. She had had a trace of it ever since that fatal morning when the greedy streetcar corporation had turned her out into the rain; but now it was beginning to grow serious, and to wake her up at night. Even worse than that was the fearful nervousness from which she suffered; she would have frightful headaches and fits of aimless weeping; and sometimes she would come home at night shuddering and moaning, and would fling herself down upon the bed and burst into tears. Several times she was quite beside herself and hysterical; and then Jurgis would go half-mad with fright. Elzbieta would explain to him that it could not be helped, that a woman was subject to such things when she was pregnant; but he was hardly to be persuaded, and would beg and plead to know what had happened. She had never been like this before, he would argue--it was monstrous and unthinkable. It was the life she had to live, the accursed work she had to do, that was killing her by inches. She was not fitted for it--no woman was fitted for it, no woman ought to be allowed to do such work; if the world could not keep them alive any other way it ought to kill them at once and be done with it. They ought not to marry, to have children; no workingman ought to marry--if he, Jurgis, had known what a woman was like, he would have had his eyes torn out first. So he would carry on, becoming half hysterical himself, which was an unbearable thing to see in a big man; Ona would pull herself together and fling herself into his arms, begging him to stop, to be still, that she would be better, it would be all right. So she would lie and sob out her grief upon his shoulder, while he gazed at her, as helpless as a wounded animal, the target of unseen enemies. "