<human>: Hey /r/Relationships, First time poster here and hope You guys can help!

Okay so I've been with my boyfriend for five and a half years now, we finally got our first flat about three months ago. 
We moved cities and we now live closer to his side of friends. 

He had a friend who was going out with this girl, they were together for four years until they recently split. 

She got her own flat and I can understand she feels lonely/needs a friend but she's round here at our flat like, almost everyday..thats not really my main concern though. 

Whenever I'm with her she seems to be fixated on me and the things I'm doing. 
Example from earlier today, I was doing the housework and she was literally watching EVERYTHING I was doing. Its almost like she's obsessed with me. She sometimes makes snidey comments also.
Is she jealous? 

And I was a bit pissed earlier, she had a lollypop and was basically giving it head like, in front of my bf. Is she attracted to him? Is she trying to steal him off me? Or am I being paranoid on that side of things and completely missing the point?

My boyfriend has also noticed her obsession over me. Its everytime we hang out.

Give me the gist of the text in a nutshell
<bot>: Basically I feel like my friend may have some kinda obsession with me. Can anyone explain why she's behaving like this?