Should I contact my advisor again about a meeting? If so, how?
If you have an "action item" that requires her okay then send an email (or other accepted communication). If you are just anxious and can proceed for now on your own then it might be better to show patience. 

As comments to your question suggest, and even the question itself, the calendar may be inaccurate. Things might have come up. Perhaps she just trusts you to carry on while she is busy. While you are dealing with only one professor, she may be dealing with several students and other obligations. 

But don't panic until it becomes necessary and don't be a pest. Half a week isn't a long time unless deadlines loom. 

But don't get yourself blocked up for the lack of a meeting. There are plenty to things you can do speculatively to keep momentum.