You're not alone!
It's a tough exam to prepare for (though I hear the exam is not that tough - don't take my word on that - I haven't sat the exam yet, it's only what I've heard! :-)
But I agree, the Head Fisrt books are great for readability, but even then you can lose focus half-way through the book and drift along for a while without doing anything.
Setting a target date is always good for any goal, it gives you something to aim at and focus on, then the work becomes a little bit easier.
As for no time - ditto! I have two kids, work full time, and my wife works evenings, so I get less time, and even less sleep. Add to that, I'm "trying" to brush up on SCBCD, Design Patterns, general OOA/D and other related technologies (JSF, Hibernate, AJAX etc.) that I need for work - FUN!
What I try to do, is one hour of study a day (generally in the morning before work - if not, on the train, even at lunch-time), if I can do more - great. This one hour every day adds up fairly quickly - if you can't do one hour - surely you can find 30 minutes somewhere - even that is better than nothing - chip away at it, and before you know it, you'll be there.