Sometimes she hated her family.
Well, not really. But she definitely has some negative feelings against them. It's called resentment.
Her mother can't seem to accept her as who she is. Her sister is the perfect daughter and seems to get mothers approval easily (which makes Arya so angry sometimes). And they never stop giving her grief over her wild tomboyish behaviour.
Arya tried to be a lady. She tried to get her stitches right, tried to make her mother proud and tried to get along with Sansa.
But its difficult.
It's just not her. She knows that she can never satisfy her mothers expectation and follow into precious perfect Sansas footsteps.
It hurts her to see that she is a disappointment to her own mother and sister.
Sansa may share her blood, but they never get along. They wouldn't have anything to do with each other if they wouldn't have been related.
At least her brothers were never cruel to her because of her tomboyish character, like Sansa.
(Children can be so cruel sometimes. Because they don't truly understand. Sansa never truly understood.)
However they teased her mercilessly over it. They too, cannot fully accept her as she is. They have their own boy things and stupid little sisters shouldn't interfere in their fun. That's what Theo said, anyway. And they know, someday Arya will have to grow up and be a stupid Lady and marry some rich Lord for some political reasons, so they shouldn't (couldn't) continue to condone her unladylike behaviour. Catelyn is a mother and she knows how to get her children to follow her lead. Robb is a good son and he will listen to her. Theo will do it because little sisters are so annoying and they should listen to Lady Stark. Because she is the lady of Winterfell and he is the ward.
Bran and Rickon are too young to truly understand the conflict over Arya's wild character. They wouldn't be able to or wish to help her either way.
Her father won't go directly against Catelyn. He is indulgent over her behaviour. He defends her before Catelyn. But sometimes Arya doubts. Everyone can't accept her. Is her father only indulging her now? Will he force her to become a lady later on in life? His words imply that Arya will later become a lady. He never truly tried to convince and stop Catelyn for Arya's sake.
Arya is smart enough to realize that her family would force her to change herself. She is eight. Not stupid. As much as she hoped that her father will help her cause, she knows Eddard Stark is a honourable man and will let the Lady Catelyn decide on Arya's upbringing.
Don't get her wrong. Lady Catelyn is a great mother and Arya loves her, even with all her faults, just like she loves her sister.
However, Arya knows she is feeling suffocated because of Lady Starks expectations and wishes. The southern born Lady cannot truly bring out Arya's full potential as a human being and warrior. Arya knows she could do much more. She knows she will be something greater than a brooding mare and a house wife. And so she decides, she has no other choice, but to run away.
The thought plagued her since her last nameday. Since she turned eight Lady Catelyn suddenly decided to further Arya's non existent Ladyshipness with a new passion.
It hurts to leave her family, but something is calling out for her. The fates. They want her to realize her full potential. Adventure and wonderful experiences whisper to her at night and she dreams of happiness as a warrior and protector, who fights and kills scary monsters. She is dreaming of it. Of following a beautiful girl and fighting with comrades. With her sisters.
She wants that.
Only Jon seems to accept her as who she is. Only Jon, her fellow outcast, tries to help her and allows her to do things that she wants to do. Only Jon helped her learn to shoot a bow, because she wanted to and told her tipps and tricks for sword play and other things. ("Stick 'em with the pointy end")
Only Jon truly wants to spend time with her as she naturally is. Not as she is when she tries to pretend to be a lady.
And it hurts to realize that nobody in the family wants to truly spend time with her as tomboy Arya, besides Jon. And she will hate herself if she leaves him all alone.
So when she feels the deep calling and the whispers and dreams... she shoves them aside. For now. It is only until Jon himself wants to leave. Mothers coldness hurts Jon a lot. And Jon wants to join the Nightwatch. There is no way that Jon wouldn't leave. She will feel lonely without Jon. She knows.
But she knows she will be long gone then. She will fill her loneliness with amazing adventures. Essos will be one of her adventures. Especially Braavos is a place she wishes to visit.
She wants to be free.
That was the plan anyway. Before the voices and visions made her fall from the tree she was climbing on. She was playing with Bran and suddenly she got visions of fighting and big scary monsters and death...
She fell from the tree and then thru a watery cold substance. Everything was bright.
She felt so light and it was bright.
And then darkness.
The next time she woke up, little Arya can barely remember her memories. Only flashes, scenes and sometimes voices.
She was all alone. In a forest. It will be a wonder if she survives.
How did she end up there? The scene doesn't seem familiar at all. Something is happening. She is needed here. For something. Obviously.
She feels so sad. As if she left something behind. As if she betrayed someone.
But she has something to do. And when its finished, she knows she will return home. Even if she doesn't knkw where home is. She feels dizzy.
Well nothing for it. She will rest now and walk later.
Arya is eight. There are not many opportunities for an eight year old little girl to survive in a forest. Alone. Well... Arya has always been adaptable. And thus she decides to find some fruit and berries...
...and promptly poisons herself.
She wonders if she will survive.