I can feel your pain
Something you say when someone is going through a tough time, like when they're crying about their pet dying and you say 'Yeah, I lost my dog and I cried so hard I could’ve drowned a cat.'
My friend's dog died and I said, 'I can feel your pain, my dog died and I cried so hard I had to take a nap.'
My brother's cat ran away and I told him, 'I can feel your pain, my cat ran away and I cried like a baby.'
My cousin's fish died and I said, 'I can feel your pain, my fish died and I felt like my heart was a dead fish.'