I have some problem like i cant really focus on important matters like if have to study today i will be thinking a lot about other things like what would be my exam results, i can't concentrate fully on things. any solution?

Can’t tell from your question if this is a new problem or ongoing. Stress may be contributing to this, so some relaxation techniques may help. Making sure you are in a place conducive to studying without distractions. Depression is another possible underlying issue. Lastly, if this is a chronic problem, consider getting evaluated by your doctor for Attention Deficit Disorder.

Physical exercise is critical as worries and mental fatigue become likely in such circumstances. Relaxing activities between your study sessions are critical in helping your brain reset.