Hi! to memorize better my studies, since I was a child, I often help myself with mental associations: it is easier to remember something if you combine it with an idea, another concept or a story, a word game .. another trick, which will need more time, is to write (or copy) the fundamental concepts or important phrases of what you are studying, when I was in high school it helped me to "tattoo" some topics that did not want to get in my head. About anxiety I think I can't help you, just breathe and believe yourself!