What can I legally do I've been abused and I can't take it anymore after five years?

I am sorry to learn of the abuse you have encountered and of your depression. Both are very serious issues. You posted your question in a forum relating to immigration law, but you did not provide any information about your immigration situation. Are you now a Permanent Resident? A U.S. citizen? Some other status? That is the type of information that could be key to answering any question you may have about immigration legal matters, such as whether you may be at some sort of risk of being removed/deported to Vietnam. While I am an immigration attorney and not an expert about family abuse, dysfunctional families, clinical depression, etc., it sounds like you would benefit from speaking to someone who does have that type of expertise. Please consider speaking to a school guidance counselor, to a clergyperson or to another person with skills in those areas, especially if you do not feel comfortable talking to your mother (or stepfather) about those matters.