I'm so sorry you're going through this. Being 16 is hard enough, without being abused by the person who should be protecting you. It is SO important that you understand that this is abuse, and that you have rights. Can you talk to a counselor at school? They should be able to hook you up with some services, and also give you advice if you are worried about your aunt harming herself.
Let us know how you're doing, and be nice to yourself - you deserve WAY better than this!
2c, 3a, something like that... Curl-curious?