It would appear that you are simply suffering from some kind of fatigue or boredom with the routine of studying. This is a common problem that tends to happen when you are continuously assimilating knowledge and is actually one of the failings of adult education. However, just to be absolutely certain that there is no other issues, it is always advisable for you to eat a proper diet that is rich in vitamins and minerals as these could have an effect on cognition. These are called nootropics, and a little bit of research on them could do you a world of good when it comes to improving cognition. The final word on what you do need nutritionally is: zinc, choline, all the B vitamins, coffee, and iron.
Nootropics are a wide variety of foods and drugs. The understanding of what makes up cognition is a bit difficult to actually pen down but it is important to understand the way that the brain works. The brain makes neural connections every time it encounters something to learn. This connection is then reinforced by using that knowledge. Now at a molecular level, nerves transmit signals using bio-electricity but this is not a continuous circuit. At the end of every nerve synapse exist a cocktail of neurotransmitters that are released and received by another synapse. This is how a neural circuit is completed. These neurotransmitters are synthesized in the brain and other parts of the body and don't have to be directly acquired from the diet; however, some essential nutrients are required for their synthesis. Choline is a base for acetylcholine and is in its maximum concentration in eggs. Even if you are a vegetarian, a healthy intake of vitamin B is all that you need. Vitamin B complex consists of a wide number of subunits and nearly all of them can be acquired from dairy and meat. Alternatively, you would need to take supplements of this vitamin. Iron is an essential nutrient because a deficiency can cause improper distribution of oxygen in the body. Finally, coffee is a stimulant and from that perspective is as potent in the right quantities as methamphetamines. This will basically stimulate your brain to be alert and assimilate more.
From an educational psychology perspective, whenever you feel that you are filled with too much work or that you are not mopping up enough study material as you should, just take a break and distract yourself with some other method of learning instead.
answered by G M