..I ermmm.... well.....

[Kestrel]

I think there might be something wrong with me.... But I dunno what.

I have this other...person... sort of... inside my head and she takes over sometimes.... and i can see what shes doing and she can see what im doing when im in control. and she can take over for 10 mins... to 2 or 3 days.... I've never mentioned this to anyone properly before. And I self harm, I have an ED and I have trouble dealing with stuff and spend a lot of my time by myself, talking to her. Is there something wrong with me? am i going f*cking mad?

[I.Heart.And]

It sounds like it would be a good idea for you to bring these issues up with a doctor.
It sounds like this 'other person' is in fact just another part of yourself that you go to for security etc. Do you have negative or positive conversations with the 'other person'?
Can you literally hear their voice?

Just my take on it.
You aren't going mad.
xx

[Stellata]

What happens when 'she' has control?

[Kestrel]

SHe's does things that i'd think about doin, but wouldnt ever do. And shes really over confident and full of herself too much... she causes big arguments then everyone blames me cause they dont know about her.

[Stellata]

So, she's all you wish you could be, but don't feel brave enough to be, maybe? Like when there's a window of vulnerability, you lose all your inhibitions? And that because you've not practiced this assertiveness thing, she's kind of rough around the edges and can mess things up... Or maybe something in you needs an outlet, and is finding it's way.
This can happen as you try to find balance within yourself.

[Kestrel]

SHe does bad things that i dont want to do either... and stuff that i would do, but its bad and you;re not meant to.

[Stellata]

It might help you to read up on the Jungian concept of 'The Shadow'. Everyone has one, just it can be more pronounced in some than others.