Honestly, it's kinda sad you don't understand how people can have an outer self and an inner self, that the outer self is what you present to the world and the inner self is feelings, emotions, and anxieties you keep hidden and often repress, that just because someone can seem perfectly fine and happy on the outside that there can't be things they struggle with under the surface.
You've taken Josy completely at face value, you think that just because she shows a certain personality and is able to have fun and enjoyable moments in life that this means there can't possibly be anything she struggles with, but not only is this not true of Josy it's also just not true of people in general. The happy-go-lucky, bubbly, friendly, party girl isn't necessarily their entire self, outside and in. Just because they can be like that and it's the person you see does not mean they aren't wrestling with some personal issues you're not seeing. As Brad Meltzer said, "Everyone you meet is fighting a battle you know nothing about", and this is entirely true of Josy.
Everything she said in Ep 11 are those battles for her, she's been keeping them to herself, and the signs were there, you just missed them because you took everything about her at face value.