how was gregors health before his metamorphosis?

Gregor's health before his metamorphosis seems to have been completely normal. He's already morphed at the opening of the story, but I don't remember any talk of illnesses or developmental problems. I found the following excerpt for you to describe what has happened;

Gregor’s transformation completely alters his outward appearance, but it leaves his mind unchanged, creating a discord, or lack of harmony, between his mind and body. When he first gets out of his bed after waking, for instance, he tries to stand upright, even though his body is not suited to being upright. He also thinks of going to work, despite the fact that he can’t by any means do so, and when Grete leaves him the milk at the beginning of Part 2, he is surprised to find he doesn’t like it, even though milk was a favorite drink when he was human. In essence, he continues to think with a human mind, but because his body is no longer human, he is unable at first to reconcile these two parts of himself.

As Gregor becomes accustomed to his new body, his mind begins to change in accordance with his physical needs and desires. Yet he’s never able to fully bring his mind and body into harmony. Gregor gradually behaves more and more like an insect, not only craving different foods than he did when he was human, but also beginning to prefer tight, dark spaces, like the area under his sofa, and enjoying crawling on the walls and ceiling. (Through these details, the story suggests that our physical lives shape and direct our mental lives, not the other way around.) But Gregor’s humanity never disappears entirely, and he feels conflicted as a result. This conflict reaches its climax when Grete and the mother move the furniture out of Gregor’s room. Gregor initially approves of the idea because it will make his room more comfortable for him physically. Without furniture, he’ll be able to crawl anywhere he pleases. But realizing that his possessions, which represent to him his former life as a human, provide him emotional comfort, he suddenly faces a choice: he can be physically comfortable or emotionally comfortable, but not both. In other words, his mind and body remain opposed to one another. Gregor, unable to relinquish his humanity, chooses emotional comfort, leading him to desperately cling to the picture of the woman in furs.