I guess it doesn´t feel like my "niece" because my sister does not really feel like a "sister" to me anymore.

This is also due to lack of contact of course (which is a good thing and we worked out in therapy).

It´s really strange, a few weeks ago I was at a party and when I said something about my "sister" it felt very strange, it sort of surprised myself to hear me say the word, because I don´t feel like I "have" a "sister".
I don´t feel like I have a "mother" either which is also very strange.

For a few years I´ve been feeling like an individuum without family, even though biologically I do.

I`m not sure if this is a good or bad thing, really. My boyfriend says it´s a protection mechanism, I don´t know.