Hi. If you see the points you have mentioned, you will see a vicious circle. They all are connected. I would suggest you to meet a counselor and work on your self confidence and concentration. Generally fear of failure is attached to this low confidence which further spreads and you procrastinate. Help is just a text/phone call away, don't hesitate and ask for it. Read up on mindful studying as I have seen that it helps you to concentrate and be aware of these distracting thoughts. Hope this helps.