After the operation, I became very weak.

Abdominal surgery itself can't hurt the vitality, but the gas in the abdominal cavity is sealed. The up-and-down movement of the diaphragm is an important part of our breathing. After abdominal surgery, the amount of gas in abdominal cavity will inevitably change, which directly affects abdominal pressure. Therefore, after abdominal surgery, it is not suitable for breathing for a while.

This is a short process, and you will get used to it soon, not to mention hurting "vitality".