My name is Kiki and I am 12 years old. I also become extremely upset when I am alone, and I get frequent headaches, not migraines needing serious medication, just the sort of thing Panadol fixes.
I am used to keeping my depression and inner thoughts to myself, so I haven't really told anyone. I have considered telling my parents so many times but my mum seems so depressed as well at times. I worry about her, and it only makes my depression worse, so I don't tell her.
Enough about me. I think that if there's anyone else you can talk to, definitely go to them. When I feel extremely alone, I like to write my thoughts in a journal. It helps me a lot and afterwards I feel so much better. Normally when I do this its when I'm in bed, but can't get the overwhelming thoughts to clear. After I write, I can sleep easily. I highly recommend this for you and others in similar situations.
I hope you find the best way for you to be the best you possible. Good luck, remember you are loved.