Its a hard one because you don't know how she will react. If she is indeed a little crazy and you work with her then things might get messy. I would just not text back until ready, distance yourself from her slowly. I'm in the process of doing something similar with a "friend". Except this friends dumps all her life problems on me and runs, if I need something she couldn't care less. I'm just not replying to every text and slowly distancing myself it takes a while but eventually they find someone else to cling too.