The most common and most likely answer to this crossword clue is the 8 letter word HARASSED
I've seen this crossword clue in The Times
H
A
R
A
S
S
E
D
More clues leading to the result HARASSED
- Made haste to protect animal under stress
- Ran quickly — grabbing donkey under constant strain
- Much-troubled Texan behind electronic parts firm
- Annoyed, ran over fool
- Under pressure, has to collect artist with second edition
- Idiot will have rushed around, under pressure
- Under pressure, ran over nincompoop
- Ran to protect fool, being worried
- A small animal circled a larger animal with some dexterity and irritated
Buddy explains!

The straight part
We know that "under stress" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case under stress = harassed.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does HARASSED mean?
HARASSED verb- To fatigue or to tire with repeated and exhausting efforts.
- To annoy endlessly or systematically; to molest.
- To put excessive burdens upon; to subject to anxieties.