Hey there Lachlan! I totally understand your situation, as I have had this struggle many times before. Just the other day I thought I had lesson 24 and all of its glory down well enough to move on. Then Papa G helped me out with some theory things I was confused about and pretty much opened up Pandora’s box for me. I went back and had so much more to apply.
My biggest thought, is that you obviously don’t know the theory ENOUGH. Like me, I thought I had lesson 24 down to a science, but I didn’t. You may know all your theory, but if you haven’t spent time applying as you move along your knowledge is kind of pointless. It’s like saying you know how math works and its principles but can’t actually solve an equation. The good thing is, is that there are many ways to remedy this. It sounds like you’ve become a culprit of the infamous “bit off more than I can chew sybdrome.”
Start with C major. Learn its key, the Roman numeral chords with it, and learn the seven different modes and pentatonic shapes you can play. Then learn licks. Then try writing a simple solo. Blues are such an easy way to get familiar with theory. I spent 3 months on lesson 24 and in that lesson, Papa G teaches you things you can do and how to apply what he taught you.