It is a BIG learning curve at first. You may be rushing the learning process by trying to FMQ an actual quilt already. I didn't try FMQ anything "real" for a couple of months. The cat got some nice quilted practice sandwiches to sleep on though.
Make up a whole stack of 12 or 15 inch square sandwiches to practice on. Spend a little time at it every chance you get, and your skill will improve dramatically over time. Save your practice pieces and you can see your progress.
I practice my quilting on a small sandwich first EVERY time I sit down to work on a real quilt. I'm not great at it yet, but things are looking much better!
If the FMQ isn't working out for this charity quilt, you may want to try doing some wavy lines or a wavy grid with a walking foot instead if that's an option for you.
Good luck, and keep practicing on small pieces until you're happy with your work, then try a small quilt again.