You Don't Get To Tell Me About Sad

This is another line from the Tortured Poet's Department. It's from the song "Who's Afraid of Little Old Me" On the whole, this song tells us a story of a girl who wasn't really taken seriously. As the title of the song tells us, the world never thought that this girl could do anything. No one was afraid of her talents. 

I feel like this line is telling us that everyone feels sorrow and grief in different ways. You can't make a person feel things in one particular way. Everyone has different ways of expressing emotions. It's telling us that no one can really tell you how to feel. Your emotions can't be controlled. You have the right to feel what you want, when and where you want to. No one can tell you not to do so. 

Another lyric from the same song is "You wouldn't last an hour in the asylum where they raised me." This tells us that everyone's problems are their own. Everyone has their own past and skeletons in their closets. No one knows about what you have gone through, but you. And that's okay. You don't need to feel the need to make everyone understand what you have faced. (It's okay if you want to share it with a couple of people, but it doesn't need to public knowledge.) 

So, since no one knows what's happening, they don't get to tell you how to feel. They can't tell you that you can't be upset. That's the main idea of this line. (In my opinion)