Mytai,
I'm no expert, but my hunch is your little is just very young and pre-verbal, so words don't sink it for this part to integrate. Even four year olds usually know not to run out in front of cars, so probably 3 or younger.
I had a little younger than 3 take over once, and I felt way more crazy because the youngest parts have so little by way of similar energy to the current adult.
I wet the bed in the night! In my 30s! I also raised both my legs and arms up while crying as if begging my mother to come back and comfort me, reaching with arms and legs upward. This passed very quickly, unlike yours is.
For those parts to be integrated, we have to figure out _What they NEED_ and this is very important.
What a 0-3 year old needs is to be HELD by someone and a soothing voice. The best thing would be for you to have a supporter who feels very safe and trustworthy to come to your house, wrap you in a blanket, and wrap arms around you, and let that little babe cry for a bit, maybe even scream, but be comforted and held and told she is loved, even though she was so scared, always loved.
If this is not possible, and even if it is, I use powerful imagery to heal myself. Sometimes, you need a real person with you or nearby as backup.
Encircle yourself with pillows and wrap in a blanket, so you are in a safe, cradle "cubby hole" that holds you and makes you secure. Play comforting music.
Envision or Google up an image of the perfect mother goddess. Leave that image open on your screen. (I see Ponyo's Mother)
And I call her "WaterNymph," an Avatar I have used in the past. She should incorporate aspects of your real mother's body but embody the highest values that you hold and best aspect of yourself.
She is incapable of making a mistake or doing you harm. She is a powerful inner and outer protector. She may have an aspect of your T. You can use Wonder Woman if you want or your favorite actress or superhero.
This is your Anima. She is very powerful archetypal energy of our universal unconscious.
Let this soul mother come to you for this work. She must be created and pulled to you to soothe this particular child, and she connects to your oversoul/higher self perfectly as she is created just for your little babe who has come to you to be integrated at this time.
Wrap yourself in a soft blanket at home, and if you can pretend, pretend this wonderful, loving, protector has now arrived by flying through your open window to save your Little Frightened Babe. She is the perfect mother for this Little Girl. No matter how afraid this little girl is, this power will protect her and heal her now, make her finally safe and resting inside of you to offer you guidance in life. Her fear and her wisdom are all available now to be utilized, and in exchange, you offer her safety inside of you.
Imagine you are holding this little babe on your lap, hug a pillow, close your eyes, and say out loud "I love you, little one, and even though I'm sometimes afraid of your memories, that is all they are. I choose to take care of you now. I am safe with you, and you are safe with me." You might have to think or say it more than three times: I am safe, you are safe; I am safe, you are safe with me."
[This is scary to have to "Be Brave" for this little, whose fear "rubs off" onto you. I admit this is hard, but it works. You won't feel it working in an instant, or right away. Let the fear be there, and remind yourself it's not real, it's a bodily feeling state that the Little carried all alone for a long time, and now you are sharing in it with her for a purpose. Once you accept her as she is, you will gain all the strength that went into keeping her separate and also all her strength will be added to you.]
Then, as the fear of this little babe washes over your body, and you will feel the physical aspect of fear come over you, that is when the Powerful Mother Earth Goddess loves you the MOST. Allow her to come and surround you, imagine her arms are the blanket, and she totally fills the room, the apartment, and even the city block, so that everyone can feel her protection and love.
Let the little rock and hug yourself. Say, "Even when I'm afraid, I am safe."
Soon, the fear feeling will pass out of your body as the Little realizes she is safe with you, understood, and valued. Promise to honor her by taking even better care of your body and by finishing the stressful medical test results with attention to detail, so that both of you are one and safe.
Imagine that any time this Little is frightened again, the Mother Goddess will also arrive to protect her and be automatically summoned to allow her to feel her feelings, but also to make them be correct and also comforted.
You may even want to "ask" the Mother Goddess to name the Little, own her as her own daughter, and by naming her, promise to never leave her side.
Once integrated, the flashback will not fully return. You will occasionally be able to feel this Little's feeling, but you will not feel like you do now. It will feel "in the past" and "a memory" only. You will feel the strength of the Mother Goddess also, and the ability to discriminate from present and past fears.
Feel free to print my "crazy" post and take to your T. as one idea.
This is just one method, as someone said above, to teach oneself to integrate and heal the inner child. There are many ways. The only important thing is that you feel right about your way, and to personalize your own method of "self-nurturing."
What your Little Babe needs to be comforted or soothed may be more visual or auditory, depending on how you were then, and are now. She may need your T. to say certain words or even sing a song to her.
You may need to sing to her, a soft song that you make up, or one that soothes you immensely.
Maybe gift this child to a screening of a soothing video
Whatever this Little Babe needs, you will soon provide. It's usually quite simple and just depends on the person.
The rubber band idea will likely help during the day. But I prefer to use Scent. I use Vicks under my nose. Or you can plug in a new scent diffuser from the store, or boil a cinnamon stick on the stove to release it's oils. I find the sharper citrus or menthol, eucalyptus smells to help me the most.
Aromatherapy might be helpful to you, as might the ice cream or a certain food. Keep experimenting until you find out what you need.
Love, Muse