I think your mum might be in denial of your illness due to the fact that healthcare is expensive. It's not necessarily that she doesn't care, it's just that she doesn't want to face reality. You should probably seek help from other family members outside of your direct family.
This is assuming that you live in America though. If you live in Europe nothing hurts going to your GP by yourself and getting diagnosed with this illness. You could use the diagnosis to show your mother that you actually are ill, which might open her eyes to your actual health state.