That's not unusual—even for the doctors. It takes some time (days/weeks/months) to get up to speed; we're all still learning and there are some things that are still confusing because medicine just doesn't know the answers (yet).

I've found it helps to keep a list open when reading/learning (I use OneNote, but NotePad, Word, whatever will work as well) to take notes, put down questions, keep links & quotes, etc.

Doc