Hey-
I totally understand what you are going through right now. At this point, DO NOT contact her. No phone calls, no e-mail, no texts, NOTHING. She said she wants space - respect that. You are smothering her by contacting her, and by pressuring her, you are pushing her away. She knows where you stand. You have to control yourself. Pressure her by withdrawing from her.
I am in a similar position and see that I was doing something similar with my X. Although I wasn't calling her or contacting her after we broke up, I did all the things you mentioned before our break-up: I started to take her for granted, our relationship wasn't as fun and light, etc. I didn't do this for too long, but I started this, and it began to wear on her. In time I noticed that her behavior changed, yet failed to note that my behavior changed first. Then we started to talk about it a lot, and I now see that I was pressuring her to make a decision, and that caused her to want to be away from me.
There is little that you can do but be patient at this point. If and when you see her, just be your old self, you know, the one she fell for, and don't bring any of this heavy stuff up. Keep it light.