@JustLeaveMeAlonePlease you're eating may not be disordered but it seems that you are very self-conscious and insecure about your lower body.
So much so that you are trying to "hide" your shape by choosing baggy/oversized clothing?
In reality, emphasising the top half of your slim figure would be a better solution for you.
This site may give you ideas, you could try some of the suggestions?
The beauty of online shopping is that we can try at home and if it doesn't suit then nae bother, back it goes.
I suspect your friend's reaction is purely because her perception is that, in her eyes, you are a tall, slim woman.
"Could" it be that in your conversations with her, you are so hyper-critical of your body that she has become frustrated because, to her, you have a somewhat distorted view of how you look?
Obviously, you are absolutely entitled to decide your own body type, if she is a good friend and you have heard her type of comments from other people close to you, it could be worth some introspection, don't you think @JustLeaveMeAlonePlease 🌻