iam not alone in my body!

You should practice shielding .That was basic

Alright, while there is a possibility of a possession, there is also a huge possibility of Dissociative Identity Disorder. With this disorder, a person has two (sometimes more) distinct identities or personalities. This condition is usually caused by some trauma. While I would use energy work to oust or control the other personality, I would also speak with someone I trust, in case there's a way to look into this condition medically.

i can comunicate with it it says it wants the best for me it gets mad when i try to banish it

This can happen with Dissociative Identity Disorder as well. The chances of an alter personality being born are higher, if you've been through a trauma--physical, mental or emotional. If you have been through to trauma, I would suggest you speak with a therapist, and while you're under his or her treatment, deal with the alternative personality by strengthening your primary personality or identity. It's the personality or identity you believe that belongs to you. This will help you over power the personality, which you feel is encroaching on you.

Dissassociate disorder can also be a sign of soul damage/loss. If you lost someone or separated from someone that you could not let go of, you could have taken a piece of them subconsciously and could be suffering from the foreign energy present. When trauma occurs, parts of our energy/spirit sometimes flee inward or outwardly, leaving space that people naturally try to fill.

A shaman or medicine person should be consulted. They also act as a therapist, so any emotional or mental issues will also be addressed. They heal body, mind, and spirit.

A shaman is also a very good option and in retrospect, sometimes better than a therapist who can prescribe drugs, which can be counteractive. Thank you WhiteRaven :)

You're welcome. =)
Good to see you magiwoman. I always enjoy reading your posts.

It's good to be back, thanks. I like reading your posts too.