Recently my girlfriend of 9 months and I broke up. I fell into a small depression for a while, but naturally, with time I got better. I started talking to another girl, but I was taking things really slow, in order to respect my ex and also just because I didn't want to rush into anything I was unsure of. I came to find out out that my ex had a new boyfriend within about 3 weeks, so she must have gotten over me more quickly than I even expected. I got completely over her and decided that I need to move on to someone else. I started talking to the other girl more and more, trying to get to know her extremely well. The thing is, when I meet people, I can usually get a pretty accurate read or analysis on people by first impression. But with her, I can't. I have no idea what she's thinking or how she feels about me. It makes me halfway excited and halfway scared. She is definitely the biggest challenge I've ever faced, and I don't know how I should feel about her yet because I don't know how she feels about me.
I've been in the position where I always think about someone, but with her, I can literally think about her 24 hours a day. It gets to the point where I find myself getting more and more anxious/depressed thinking so hard about the situation. I've gotten to know her a lot better but, I still can't figure out what she's thinking and that's the part that drives me crazy. I know that I like her a lot, but I don't know if I should. Part of me thinks that she likes me, because of the way that she acts (flirty, uncomfortable in person, etc.), but the other part has absolutely no idea. I just feel like I'm completely oblivious to her, and it makes me so anxious because it's such a new feeling to me, there's never been anyone who I have no idea what they're thinking.
Anyway, in the last couple days, she hasn't responded to me, and I can't figure out why.. It's been about 3 days now, and my anxiety continues to get worse and worse. Did I cause this? Did I wait too long to make a move and cause her to loose interest? Did I simply over commit myself to her? I don't even know if she ever liked me in the first place. It would help me a lot to just know what she thinks about me or what she sees me as, whether it's just a friend or if she likes me. I just want to know before it's too late, if she likes me, I have to do something about it before she slips away.. It's literally making me go crazy not knowing. :/

Please help, Thank you in advance

My first question is have you made it clear how you feel about her? Or are you to busy trying to read her signals. Maybe your so preoccupied trying to figure her out you missed the signs and she moved on.

I haven't directly told her, I guess I just assumed she would figure it out.

Well maybe she didn't. Some girls can pick right up on it while others are oblivious and need it in black and white. Send her a quick message telling her you would like to get together.

But she's the one who didn't respond to me, I've tried to speak to her

Then there is your answer. Maybe you couldn't figure her out for a reason. Maybe you weren't compatible and that's why you couldn't read her.