Talking with someone face to face is exactly what you need to do. You have suffered far too long with this. I can’t tell from a letter whether the sleep disorder is causing the emotional upheaval and hallucinations or if there is something else going on that is causing the sleep disorder. It could go either way. Without a proper understanding of the problem, I can’t give you sound advice.
But what I can tell you is this: You need to see a professional mental health counselor for an evaluation. Share your letter with the counselor as a way to get started. Talk about exactly how much sleep you are getting and how often you wake up. If a sleep disorder is the problem, the counselor will give you advice about how to get back into a regular sleep cycle.
If, on the other hand, the sleep problems are a result of an emerging mental illness, then he or she will help you understand the treatment options for that.
You made an important first step by writing. Now please take yourself seriously and get the help you need. You don’t have to live like this. You don’t have to be “strange.” With some practical help and support, you can reclaim the girl you used to be.
I wish you well.