WIBTA for telling my mom I won't borrow her any money if she won't let me eat?

Hi guys. I have a part time job and I make a bit of money. My family is very poor, and my mother is going through a hard spot financially right now. She's living off my brothers disability benefits and universal credit (I think this is known as welfare in the UK). Thankfully she doesn't pay rent or water, because the council do I think, but yeah.

So. My mother and stepdad currently aren't doing well financially. They did a foodshop, and brought home a ton of food. Last night I went to make a turkey sandwich. My mum said the turkey was "for my brother only". She also said some other foods were only for my brother, and then for her and my stepdad, and kept going until there was basically NOTHING for me to eat.

I said this, and she said I had soups and tuna. Thats lirerally ALL. 3 cans of soup and some tuna. I don't think soup and 2 cans of tuna is enough food, personally. She just said she's "trying her best". Like yea, she is. But I'm also a person and need to eat.

She also borrowed 80 pounds from me this month. I don't make much at my job, and I have my own stuff to pay too. Would I be an asshole if I told her I'm not lending her any more money it she won't even let me have a few slices of turkey? It just seems a bit unfair to me man