German phrase
Es geht mir nicht so gut.
Meaning
I'm not feeling very well
When to use it
Says you are not feeling well. Polite and mildly formal, often used to mention feeling ill.
Example dialogue
Es geht mir nicht so gut.
I'm not feeling very well.
Das tut mir leid. Seit wann ist das so?
I'm sorry to hear that. How long has it been like this?