This is very obvious that you have to make her understand the value of your money and hard work. She should have to understand that your salary doesn’t allow you to expend out of budget every week. 
You can also start saving without telling her about it so that you can have an extra amount with you in urgent times. Sometimes we have to hide things from our partners for their and your good. Balance your relationship with her and try to make her understand without getting aggressive or irritated.