Hi guys, I read some posts and I wanted to ask your opinion on a very serious and quite complicated issue. Short time ago, I started a new work in a completely new city, met an amazing girl at work, we car-pool together once a week, and we got to talking and she started sending me messages almost every day. She's single and we hit it off almost right from the start, we crack up about many things, she made a guided tour for me in the new city, suggested that we could go to sports events etc.
2 weeks ago we went to the movies, had some drinks afterwards, made plans to see each other on the weekend. Yet I tried not to make her feel like she's the only one I like (never done that before with her, ok..

, so the next days I hardly talked to her, and 2 days later (when I didn't show up at some kind of work-related speech including an after-work event, she wrote a short message after that evening saying that the “speech” had been fine even though it was hard to follow for somebody who was at work all day. And she wrote that she won't have time on the weekend (and that she didn't exactly remember what kind of plans we had made which seemd a bit off to me...). So she seemed quite angry with me, so I wanted to make it up to her by apologizing that I didn't show up at the event and that can reschedule for another time since the weekend plans didn't work out.
Showdown time was a week later. Monday was ok, she wrote me a lot of text like always, asking about work and that she'll be at a birthday party so we wouldn't be able to car pool this week, blabla. but then 1-2 days later she almost completely ignored me, just exchanged courtesies, didn't listen when I was telling a story to colleagues with her sitting nearby. That evening we also had a meeting, this time I came, later some colleagues (incl. me and her) went for a drink. There was also an athletic guy who works in another department. Well they talked, seemed to like each other, and I went home completely frustrated because she didn't seem to give a damn about me anymore. So, here it comes, big mistakes in a row, fasten your seat belts:
Didn't sleep the whole night, figured out that the birthday-party she wrote about on monday was actually Mr. Athletic birthday party, well suddenly no attraction any more towards me, you do the maths.. I totally freaked out, had lots of images in my mind, so in the end after a sleepless night I wrote her a text in the morning that I need to talk to her right away. (If you want to start counting my obvious mistakes, you gotta count fast now

That turned out to be a complete disaster just to organize a break for both of us (somebody had to fill in for me, didn't work out, almost everybody noticed, you get the picture), and in the end I had 5 minutes (she had to leave early because she had an appointment). So I asked her if she was mad at me by chance, told her that I want to spend more time with her (yeah, i know, but it gets even worse), i gave her a present (one of these advent calendars, and not even a cheap one, told her it was mine and I wanted her to have it). So as I was just following the "how-screwing-up-big-time" manual she simply just said thanks and kept it rather vague if we can do something together next week.
Next day she wrote me this text: "Hey. I had to think about us a lot in the past few days and maybe that's why you got the feeling I was mad at you. Which I wasn't. I'm rather mad at myself. Because I think we would match really well. You're very funny, which it's very important to me, and you're a nice guy. But I don't feel attracted to you. Maybe that will change. I would really want that to happen. I just wanted to let you know. It's only fair. I wish I could tell you something different. "
Hello there, Mr. friendzone.. So i told her that I respect that and that it is better not to spend time in our spare time any more. In her answer she suggested to go out in a group and "see how that turns out". I agreed and - end of story.
We see each other at work all the time, you can imagine how awkward that is, I tried not to show anything (in fact, yesterday I was told how happy I seem

, but honestly I don't know how to deal with that, how to behave. She's a colleague, I'm new, I don't know if that was just her polite way of saying "you and me-ain't happening" , in general: What am i supposed to do? Leave that girl alone or waiting or give up? Was that it?
Thanks for reading and any suggestions!!