Major anxiety! I'm in undergrad honors quantum mechanics II. I got an A in honors quantum mechanics I. It was darn hard but I did it. My problem is that I feel like all I'm doing is keeping up, chapter to chapter, topic to topic, without anything really sticking. I feel like a total amateur at this, it's making me wonder if I'm good enough to go to grad school for this. I believe I earned my A but at the same time it seems like I can't retain anything I've learn in QM longer than a month. I can build up my conceptual understanding of other areas of physics with examples, like physics brainteasers (like the Flying Circus of Physics). Math is also a strength of mine but I feel like I have nothing to visualize, and I'm a visual learner, so it feels like I'm not retaining enough even though my grades are good. Is it supposed to be this way? Will things stick better the second time around in grad school, or does it sound like I don't have what it takes?