I'm confused. :??
Is your problem that you can't keep track of the pattern? Or is the pattern too difficult?
I once tried to knit a shawl where the pattern wasn't technically too difficult, but it was hard to keep track the stitches for whatever reason. I ended up not doing that shawl becase it took the fun out of knitting. But if I were to try it again, I would probably use a lifeline on all the even rows (which were straight knit rows in my case). Perhaps you could use a lifeline on all your purl rows so that no matter how many times you mess up, you know you'd only have to frog until the previous purl row.
Just a thought...
A Lifeline is a strand of contrasting color yarn pulled through live stitches. You'll pull the lifeland through all the sts on the needle after you've purled one row. Continue with the pattern as usual. If you ever need to frog, the lifeline will act as a "bookmark". Once you frog to the lifeline, you can put the sts from the lifeline back onto the needle. When you make it to the next purl section, relocate the lifeline.