Creak under the strain
Definition 1 of 1
Pro Tip 1/3Physical Imagery
Imagine something literally creaking to understand the metaphor for struggling to cope. 
The old bridge seemed to creak under the strain of the heavy trucks.
Pro Tip 2/3Emotional Weight
This phrase often implies emotional stress, not just physical or mental demands. 
She could feel herself creak under the strain of her parents' expectations.
Pro Tip 3/3Not Literal
Remember it's a metaphor; no actual creaking sound is involved in real-life situations. 
His smile began to creak under the strain of hiding his true feelings.