A crying emoji with an open mouth, wailing with streams of tears flowing from closed eyes. It's used to convey inconsolable grief, extreme sadness, sorrow, or being emotionally hurt.
It's also often used as an extreme form of laughing, a loudly laughing crying emoji, replacing 😂 Face with Tears of Joy as the latter became less popular.
The Loudly Crying Face emoji's meaning is tricky, mostly to its rising usage as a laughing emoji. Only the context may give you a clue. Below are examples of tweets making fun or expressing sadness.
Fun: "Bestie I'm sorry for laughing 😭", "HAHAHA I like lavender it’s fine 😭", "In case you missed it 🤣🤣🤣. I'm dead 😭".
Sad: "This is so sad 😭", "it's really depressing 😭", "I miss u so much 😭 😭", "going exam 😭".
It also may be a mix of both meanings. To show the irony of something being so sad that you only can laugh at it.