I get frustrated and discouraged at times too. But, I do enjoy quilting and sewing so I know I won't give it up. I just step back and do a small project (small wall hanging, tote, purse, accessories, whatever) till I get my quilting mojo going again.
As for discouraged about figuring the patterns out, I have the same problem. So, when I can't understand a pattern, I do my best to follow along but usually end up adapting to my own version of the pattern. My quilting buddy says I always have to "make it a little different" to make it my own.....where in reality it's just that I don't understand the instructions.
When I was diagnosed with fibromyalgia, my doctor said my brain doesn't process information the same way anymore so I've learned to adapt.
If you need help "figuring" out a pattern, feel free to email me off-list and I'll try to help out. Not being able to follow patterns is very frustrating so I feel your discouragement and want to help.
Hang in there !!!