I have never been a studier either. I haven't taken the NCLEX and I am
working on studying for it but I didn't really study at all through nursing school
and got good grades by either attending lectures/labs or reading the material. Studying is very difficult for me because I never needed to develop study habits when I was in school. Don't feel bad about what you can't do, focus on what you can do and work on ways to cover the content you need in a way that works for you.
If you can only focus in 10 minute increments then perhaps that's what you should study in. I think what you need to work on more is not procrastinating (I'm so guilty of this!) and getting back to the studying sooner rather than later! If you study for 10 minutes, take a 5 minute break and get back to it. It will take you longer to cover the material but at least you will cover it! As you get used to working for 10 minutes, push yourself to keep at it for a couple of minutes more so eventually you can do 12 minutes and then 15 etc.
Have you tried practice questions? You do need to work on being able to sit and take a 285 question exam just in case that's the length of your NCLEX. Personally I find doing questions on the computer significantly easier than going over content in Saunders.