Need some inputs. Thanks! :)

Hey everyone, not sure where I should post this so I thought I might as well post it here too.

Hey guys,

I'm a bit stuck in the middle here so hopefully some of you are willing to help me out as I appreciate any help or advice any of you can give me (especially from the female point of view).

Basically the situation is this, I've known a girl from a long time ago. The relationship had been mostly a brother and sister relationship until recently we got way closer. We were pretty close as with the brother and sister relationship to the point where we were calling each other that. But then recently, I think the relationship was brought to a different road as she never called me brother anymore. Never asked and don't know what the reason behind it is.

Nowadays, we would talk practically everyday on the phone and at the least she would call me up before she goes to bed to say good night or text me saying that she can't call me but to just say good night. Also she would also end conversations with some kind of "heart you" to it - (not I love you).

Also another thing I've noticed is when I would ask her about where she is going or how was her day. She would make sure every time she goes out with a male friend, she would clarify that they're only friends.

Once a while, I would be talking about a female friend of mine. From the look of it, she was acting differently but when I asked her if she was okay, she kept saying she was okay. At this point, she asked me if we could talk another time (I believe I was telling her about a friend of mine who I thought was good looking).

Anyway, what do you guys feel or think about this case?
Does she have any particular feelings for me or do you think it's more of a casual flirting or brother/sister relationship that I never experienced before.

Hopefully some of you guys are willing to give me some insights on your point of view.

Thank you so much and have a wonderful night.