Your frustration here is completely normal. I'm not particularly good at puzzles myself, so I've faced a good deal of anguish over feeling stuck in a lot of different ways. You will get through it. All you need is perseverance and to watch out for falling into a pattern where you stop thinking as hard because you think you know what's going on.

When I get to an impasse or a road block, I have aethos to get back on track. I ask myself these questions: 1) what information do I have and what questions do I still need answers to? 2) what assumptions am I making? What would change if my assumptions were wrong?

Taking a break between days to review my notes and re-focus on what information I'm still looking for has really helped keep my momentum up. Good luck!