I think u may be u are facing any mental pressure, over stressful life or anxiety and depression. These all may effect ur attention and concentration and lead to decrease memory. Do not loose hope and try to increase urvself confidence. Trybto point out the actual cause of ur mental pressure if u have any and then solve each of them. If u cant do it alone then u can consult psychologist online or offline and take help to live a healthy life.

Hello. Failure is when you don't try at all! As long as you keep trying, you're not a failure. You may find it hard to revise the Quran now, and that's all right. It is necessary that you stop judging yourself. Besides, this is not a terrible situation that you are finding it difficult to revise. If you start slowly day by day, you will certainly be better than the previous day. And that's progress. Action will remove all doubts! Action is what we can control, not the fruits. So, start revising as soon as you can.