A person cannot do something itself illegal to cause you emotional or mental abuse, such as threatening you with violence or extortion, or posting harmful things online under your name, as if they were you, etc. But the law does not prevent person A from saying harmful or hurtful things to person B; it does not prevent them from doing things that are legal for them, even if it is a "trigger" for another person (e.g. say a person is sensitive to and distressed by loud sounds; since it is legal for a person to play music, however, that person's roommate could legally play his/her radio); and does not prevent a person from disclosing information you shared with them (e.g. about your mental health status) with others, unless that person had signed a confidentiality agreement of some kind (when you tell things to another person, you run the risk they will repeat them). While this is unfortunate, it does not appear anything actually illegal was done other than throwing away your belongings: you could sue for the value of what she disposed of.