Do you understand how it feels to miss someone? It feels like spending a long time turning the ice-cold water you have drunk into tears.

^^^ I have never heard this expression - it sounds very interesting! However, it might not be understood by English people.

This is a really cool saying!

Removing the word {that} would be how I'd say it as a Canadian.

(And we use a period {.} to end the statement.

Do you understand the feeling of missing someone? It is just like you will spend a long hard time to turn the ice-cold water you have drunk into tears.

(You can also experiment with other English words find another English flavor).

Do you understood the feeling of missing someone? I've been waiting a long hard time drinking iced water to fuel my tears :(...

PS: I think I double posted. My other post got squished together, haha!

Missing

Do you understand the feeling of missing someone know how it is to miss someone1? It is just like that you will spending a long hard time to waiting for the turn the ice-cold water you have drank turn into tears!

Good comparison of time!

1.  There is nothing wrong with the grammar.  It is not the way we usually express it.  It is like in Chinese, 寒冷 but not 冷寒