Exactly, more than a week without contact is easily her doing something she shouldn't be doing or her having little to no interest in you. It just shows she has little to no concern for you. Nobody is that busy that in this world of mass communication that they can't take a minute to send a message to let you know how they are doing. I remember when dealing with women and they were really into me, they'd even put their family on hold or talk to me while their family was around. They never happened to be 'too busy'. The 'too busy' thing came up when we were about to break up.
Let me tell you what 'too busy' REALLY is. It's her being interested in another guy but wanting to put herself in a position to keep you hanging around in case he doesn't work out. If it DOES work out with him, she'll hit you with the 'we need to talk' ordeal and say how she wasn't getting what she needed, etc... If it doesn't, all of a sudden she will become unbusy, but when she comes back, she won't be as available or into the relationship as before... she'll start disappearing more and more often. In this situation, what you do is you simply tell her, "look babygirl, I'm going to let you focus on whatever you have to do over there, but I'm moving on." Give her the boot and keep it pushing. Don't let these women play chess with you, keeping you as a back-up.