If you’ve got too many active projects for you to get your mind around, I would suggest temporarily moving some of them (the least-developed and least-urgent ones) to your “Someday/Maybe” projects list. This will help you see your list and feel more in control of it, then you can move things back into ‘active’ status as you begin to feel more comfortable with the system.

I used to be scared of a too-long Projects list as well, and I created all these nebulous, umbrella-shaped meta-projects like “Manage computer security” to swallow up all the tasks involving security issues (I’m a systems administrator in a research lab). However, that really didn’t end up working, and though my Projects list is now much longer it provides me with a much more accurate sense of direction in my work.