Am I over thinking things or do these things mean something?

First read my original thread: /threads/69864-Fell-in-love-with-a-questionable-girl

Now I need some female advice on some things.

This girl acts a certain way whenever she is around me and I'm having a very hard time understanding what she is thinking, and I'm starting to think she is losing interest.

Despite her avoiding bringing me into her private life she talks about her family constantly, something which she says she doesn't do to her "clients".
Furthermore, there are times where we will look at each other in the eye for a while without saying a word and I really can't tell what it really means. I have flat out asked her if she was bored of being around me and she denies it and simply says she is in a pensive mood. So far our relationship has been sort of a friends with benefits sort of thing but I couldn't help falling in love with her and wanting to bring things up a notch. It seems to me like she likes me but has a reason for not wanting to get involved too deeply, perhaps because we met in the wrong circumstances. Having spoken to her friends it seems that there is an attraction on her part as well. How can I tell if I should press further or leave things as they are?