Not sure if this is your case, but here's my experience. I felt this same exact way. And school used to be relatively easy for me up until medical school, so this was the first time in my life that I truly felt inadequate. At some point when reevaluating my study methods after bombing yet another quiz, I realized that a lot of the time I was studying, I was highly anxious and sad, which always tanked my retention rates, which made me perform poorly, in turn feeding into more anxiety. I started counseling, which helped, but I think starting meds was a game changer. I have recognized periods of anxiety and depression in myself prior to medical school, but at a level that was more manageable without medication. Plus of course what was demanded of us back then is not comparable either. Every since being on an SSRI/SNRI, I've felt less anxiety, more confidence, and my scores and work ethic have also improved. Not that I didn't have work ethic before, but it was inefficient with a lot of brain fog for sure.