Why is my mum constantly buying clothes too small for me?

I'm so sick of my mum right now!! My birthday is on Saturday and she has gotten me a lot of clothes. She was showing them to me (she got them on Ebay) and I looked at the sizes, I am an Australian 14 and she is getting me size 12 and 10 clothes, I appreciate her getting me the clothes but it hurts because I told her they wont fit me and she said I will just have to lose more weight. Last november I gained 25 Kgs due to medication and have lost 15 of them and am working really hard to get rid of the rest but even when the weight is gone I will be the size I was before and I will still be a 14. It hurts because I feel she is pushing me to lose weight and I feel like I'm not good enough, She is big too but weighs less than me and she rubs it in. what can I do. I dont feel good enough.