Does she hear voices, or have any hallucinations? Does she seem out of touch with reality? Could be paranoid schizophrenia. She also sounds like she has OCD (obsessive compulsive disorder). The fact she does not take care of herself sounds like depression. However, when someone is schizophrenic, all of these signs could appear. She would need to be evaluated with a mental health professional asap. The fact that she is suicidal and may even have a plan is a true crisis emergency. Does her parents know? If not, they need to get her help fast. You sound like a true friend and have good reason to be concerned for your friend. If she does turn out to be schizophrenic, there are medications out there that can help her. Ignoring the problem would only do her injustice. Let us know how things turn out. I will say a prayer for you and her.
Sounds like it could be a mix of things...Im only familiar with anxiety and depression and it certainly sounds like she could have both going on. Either way, you should encourage her to seek help. Therapy of some sort can really help sort out everything thats going on in her head. You are a very kind and good friend to be posting for help for her. If she is having suicidal thoughts...thats a sign something needs to be done to help her. Maybe talk to her mom or parents? Or if your really worried schools typically have psychologists or at least guidence counslers.
Again, thanks for posting...you are very kind to do so. Stick by her! she is obviously going through a rough time in her life and trust me, she needs her friends more than anything right now.
I wish you and your friend well.