In The Metamorphosis do you think Gregor was like a "bug" even before his metamorphosis?
Gregor seems to unconsciously realize how his position as a salesman has stripped him of his humanity. He thinks that "'This getting up so early . . . makes anyone a complete idiot.'" Further, when he thinks about what his work has done to him, he considers "'the torture of traveling, worrying about changing trains, eating miserable food at all hours, constantly seeing new faces, no relationships that last or get more intimate.'" His job has turned him into nothing more than a worker. He feels that the demands on him are inhumane, and he—quite tellingly—doesn't even have the time or opportunity to form any intimate relationships that might make him feel like a human being again. His life has been stripped of all the enjoyable things that make a human life worth living. In a sense, he has been treated like little better than vermin—even the manager who comes to his office talks down to him harshly, even cruelly—and he must plead for some semblance of respect.
Before his transformation, Gregor is valued only because he is a worker, not because he is a person. When he feels himself unable to get out of bed to go to work, he thinks of himself as "'useless.'" His only purpose is to work. Like an ant in a colony, he is easily replaceable by another of his kind when he becomes to weak or sick to continue. In this way, then, his figurative transformation occurred long before his literal one.
This is a really interesting question. Although we are only presented with Gregor when he has been transformed, and so we never see him before he experiences his metamorphosis, we can infer quite a bit through the text about his previous life.
Note how in the text it appears that Gregor had very little social life - he had no friends from work or elsewhere and he definitely did not have any lovers. Likewise, it is clear that, apart form his sister, he does not have close relationships with his mother and father. Even the relationship with his sister seems to be based on a false assumption, for it turns out that she betrays him. He clearly follows a life characterised by isolation and loneliness even before his transformation. The metamorphosis therefore only exacerbates these characteristics because he cannot communicate and he is kept in his room, locked away from the rest of humanity.
Another aspect that we can identify as being similar is the way that Gregor's life was all about working in a job that he hated for the benefit of his family. When he is transformed, Gregor can hear others and discover their wants, but they are unable to find out what he wants. This is ironic, for Gregor's life seems to have been all about meeting the needs of others whilst his own are forgotten.