As in: "ugh(?)", is it him again?
2 Answers
Ugh can be used in your example. It is the sound that people make when something is extremely unpleasant (Longman Dictionary of Contemporary English).
The sound itself is called a harrumph. You could also call it a grunt or a sigh depending on the exact connotation you're looking for.
If you are looking for an onomatopoeia, "ugh" is probably the most common spelling. Others include "ack" "blech".