What is Gregor's present source of stress (other than his transformation into an insect)?

The Absurdity of Life

Beginning with its first sentence, The Metamorphosis deals with an absurd, or wildly irrational, event, which in itself suggests that the story operates in a random, chaotic universe. The absurd event is Gregor’s waking up to discover he has turned into a giant insect, and since it’s so far beyond the boundaries of a natural occurrence—it’s not just unlikely to happen, it’s physically impossible—Gregor’s metamorphosis takes on a supernatural significance. Also notable is the fact that the story never explains Gregor’s transformation. It never implies, for instance, that Gregor’s change is the result of any particular cause, such as punishment for some misbehavior. On the contrary, by all evidence Gregor has been a good son and brother, taking a job he dislikes so that he can provide for them and planning to pay for his sister to study music at the conservatory. There is no indication that Gregor deserves his fate. Rather, the story and all the members of the Samsa family treat the event as a random occurrence, like catching an illness. All these elements together give the story a distinct overtone of absurdity and suggest a universe that functions without any governing system of order and justice.

this labor, by slow prudence to make mild.   c. ability to govern well