My friend and I

I have a lovely friend. She can be everywhere with me and never leave me alone.

* When you say "and never leave me alone" it gives the impression that she is bothering you. I would say:

She goes everywhere with me and never lets me feel alone.

Whenever I feel sad, or have any problems, I talk to her and she helps me to find the solution. As I know she is so very powerful. She gives me self confidence to be strong, and she says: "Hey, don’t worry! I’m with you!" I think we love each other. I talk to her about even small things day and night and she never gets tired of me.
I talk to her when I’m happy too (although with a little late).

(I don't know what this means. "Although with a little late" doesn't clearly express what you mean. Do you mean that when you're happy, you talk to her, although usually a little later? Or do you mean something else? Maybe it would be best to say:

I tell her immediately when I have problems, and also talk to her when I am happy.)

Because I think friends must be with each other both in happiness and pains ;-). I love my GOD (her)!

This was very nice :-). I hope my corrections help, and it must be very special to have such a wonderful friend. She is lucky to have you, too!