It means “I love you so fucking much but I know you probably don’t love me back” is usually used to tell someone you like them without actually telling them.
I love you so much that my heart stops beating when you're leaving
And I'm grieving and my heart starts bleeding Life without you has no god damn meaning
I love you so much that my heart stops beatin' when you're leavin'
And I'm grievin' and my heart starts bleedin'
Life without you has no goddamn meanin' - Tyler, the creator. thats his lyrics from the song called “IFHY”