Go through the mill
Definition 1 of 1
Pro Tip 1/3Stressful Experiences
Used when someone has been through a lot of difficult or demanding situations. 
She's gone through the mill with her health issues recently.
Pro Tip 2/3Emotional Impact
Highlights the emotional toll of the hardships faced. 
After the flood destroyed their home, they truly went through the mill.
Pro Tip 3/3Metaphorical Mill
Imagine a mill grinding down grain; this phrase compares life's hardships to that process. 
Years of legal battles have really put him through the mill.