If you feel this way, it just means it’s time to get back to the basics/fundamentals. A step at a time can help to build confidence. For the LR, I'm working on analyzing arguments for strengthening, weakening, sufficient assumptions (SA), etc. But it’s a series of steps which starts with recognizing the question stem, proceeding to identifying the conclusion and support. Then knowing, for example, that it’s an SA question, I’m expecting a gap in the reasoning, such as some relatively weak support based on the assumptions. This means that while I’m reading I’m not struggling with understanding disjointed reasoning since I expect/anticipate it to come in one of its known and familiar argument forms. Having gone through the valid and invalid argument forms lessons, I’m confident that I have a clearer, and perhaps intuitive understanding of how to proceed with these repeated argument forms. The series of steps can seem mechanical which is why practice is needed to almost automate this process as habits based on solid fundamentals become instinctive. Maybe writing down the steps you must go through to tackle a particular type of problem can bring clarity and ultimately increase your confidence.