As the title says, I would like to hear your opinions on situation that I will explain below. I appreciate your help.

The story begins last year in Uni, where was this girl in my class (about 250 students), I noticed her looking me somewhere at the end of school year, later I got her name and number, she added me on FB, but becouse it was end of the year we all went home for summer. During summer we texted a little, but never met becouse of distance, summer jobs,trips (it wasn't even that important to me).
This year when classes started me and my friend and she and her friends (i don't really know how this happened) formed a, let's say, little group. Me and my friend are basically friendly with everybody, but this 4 girls are only hanging together or with us. That means coffe brakes, partying etc.
Back to my problem, I asked her on a date, she said yes and on a date she was like, i don't know how to describe, she was cold I guess. Even if I wanted to I couldn't make a move-for example she walks 1m away from me. And every information I needed to pull out of her. Ok, you would say she isn't interested, but the problem is this: when we aren't on date there is a lot of eyecontact, Tension, during texting also, she said yes to go on a date. So let's say she is shy, ok, second date - the same. And then when she is drunk, she dances with me, she is hugging with me, but that's it.
Then I said, you know what, I guess this is friendzone all over again. Then she invites to a movie, but during date her body language was terrible towards me. And at one point she puts effort in conversation, she asks questions and than in one moment she just stops and goes back in her shell.

It's hard for me to explain the whole situation and what I wrote isn't even near to whole story. I know how it feels when a woman likes you and how when she doesn't. And here I get both sides. She's hot&cold, but I really like her.

So guys, what do you think I should do?
* Just let this one go and stay friends so I don't f*** up the group
* Let go and let go the group also
* Or should I speak to her and tell her I like her and find out what's going on - despite I might hear "i see you more as a friend" and probably will be akward in group then. But then it doesn't even bother me that much that I'm again in friendzone, becouse at least I will know how the things are.

Man, did I complicate ...