First of all, stop wasting your invaluable emotional energy in self deprecating guilt. Dont pay any attention to what does not matter and that which does not in any way contribute to your confidence, optimism, hope and perseverance. Focus only on what is top priority. First, your peace of mind. To get there, you need to focus on your breathing mindfully with awareness on each inhalation and exhalation. Place your palm on the tummy and breath as if your lungs are there and feel the tummy move up and down. The number of breaths should be about 11-12 per minute. Secondly, talk to yourself positively. Words are very powerful, say to yourself words like I am calm and at peace, I have a good memory and focus, I can understand clearly, I can do this, I have the capability, I will be at ease while studying etc., Thirdly, if you get stuck somewhere, just may a note of it on a paper and move on. Dont suffocate and get obsessed, just move on with what you can. Then afterwards, deal with what you are stuck with separately one at a time. Ask, seek and find out solutions and information from the sources you know. Fourth, learn to relax, do some stretching exercises like bending, turning around at the waist and so on. Then, sit in a chair or lie down and focus on your breathing and do a scan mentally, like saying a feeling of relaxation is entering through my toes and moving up slowly into the ankles, shin, knees thighs and all over the back. Next, it is moving up over the tummy, chest, neck and now it is starting in the fingers and moving into the palm, wrist, forearm, shoulders and moving up into your face. Your breathing is becoming deeper and slow. Your mind is becoming calm and peaceful, you are now in a state of deep relaxing, stay like this for a while and then repeat. Bring into focus the problem you have and affirm you will get answers. Stay like this and visualise your self being sure and confident. Leave the problem to your subconscious mind to find a way out. You just wait and listen, dont worry about it. This simple exercise will condition your mind to be solution focused instead of problem focused. The solution may just pop into your mind when least expected. This technique can be used to relax and give commands to the sub conscious mind like, I have a good memory, I can do it, I will find the solution to this problem, I have good understanding etc.
Next, always speak of your self positively and dont worry about the results and outcome, just focus on the effort and perseverance. Do your duty well and that's it. Dont think about what you cant control, change or reverse. Just be in the present and focus on the work at hand. Give commands to your sub conscious mind when you are just about to sleep. This is a relaxed state and your commands will be followed by the sub conscious mind as per your wish. So, dont despair, just do these simple things. Believe you can, visualise you can, feel you already have done it. You have done it before, you can do it now as well. Throw out the garbage and clutter. Just use the time to your advantage. Plan, schedule, monitor, remind yourself and just go about doing.