Hello Jane, Weak memory and lack of concentration is known to be from PMO symptoms, that will effect the person's grades and studies. I am facing it, a lot do face it. It will improve and totally recover while doing nofap. Sometimes a person suddenly feels like can't concentrate or think about anything, this is a part of Brain fog, which is another side effect of PMO, but both of these symptoms and most of other symptoms will recover as the person is rebooting You can do it, don't give up!
Things will heal by time, just keep persisting in the process, it may take time because it is a whole process in creating a healthy lifestyle, don't ever be discouraged and be proud of every single process you make!
You are a legend. Yes it is related . Masterbation is very taxing on the nervous system . It f*cks up every aspect of your life. Period