I would document what has been going on since she has started these medications. I would also makes sure that the psychiatrist and psychologist are aware of how you feel. Hormones have absolutely an affect on a person's mental state and awareness. If she started her period for the first time, I can imagine that she is going through a lot. I wouldn't disregard the thought about her hormones being in the mix too. With all of this going on, I can imagine it is very hard for you to deal with and process.
I can tell you that with any medication, you may not see a difference until about the third week or so. If you are feeling uncomfortable at any time, and believe that she the medication is making her worse, I would consult with her psychiatrist.
If she is pre -teen I also would encourage her to write her feelings down in a journal. It helps to have somewhere to vent to, and it's important for her to feel comfortable enough to express them. I want to make sure you are aware that even though she might be stating that she wants to hurt herself, and that she feels suicidal, etc. it does not mean that she will do it. Have you noticed any bruises, cuts, or other punctures on her body? It sometimes is the only way to tell someone how you feel. However, obviously it is a concern that she is stating this , and not to be taken lightly. I just want you to know that sometimes it is better that she is stating this, and not keeping that feeling inside. You are better equipt to find her help and prevent a very bad outcome.
Feeling like you want to hurt yourself is an indication that she is feeling an extreme amount of pain,hurt, and aggression. I am sure a lot of it is from her unability to voice her feelings, as well as how she feels about the divorce. She is looking for a release from her pain.
My advice is to help her release this pain in a positive way. Drawing, painting, music, photography,caring for an animal, excersize, etc. Does she have a particular hobby?
It will get better if she is on the right medication, therapy, and a good relationship with family and friends. She also will need to feel safe,secure, and comfortable with herself and her feelings.
I have worked in the mental health field , and also have two brothers who went through a depression. One of whom is Bipolar. I can tell you that he has his good days and bad days. A supportive parent, friend, and therapy team is vital on how well the symptoms are managed. The fact that she is so young, is good, and the fact that you were proactive in getting her into treatment is also very good.