Answer:
It happens to all of us, and it could be very overwhelming, however, there is several ways to conquer the huge amount of work easily, without stress.
Try to breath and stretch while your studying. Breathing techniques are one of the quickest and easiest ways to relieve tension in the body and calm the mind.
It's also very important to manage your time correctly, creating a schedule of how much time you should spend on this subject and how much time on that topic is very impotent, it organizes your work and allows to finish your work with ease.
Make sure you have nothing to distract you, try to find a quite place with nothing to distract you, also, get rid of any electronics that could distract you.
Excersize! It's important to get your heart pumping and ready to do work, whenever your starting to feel a little tired, get up, do some jumping jacks! IT will energize you and you'll feel better very quickly.
Surprising, writing down your problems or talk it out to someone else helps, It always helps me, knowing that their is someone else to be their for you is a reliever, and perhaps they could help you with your work!
Remember, you'll be alright in the end, it just takes time.
Hope this helps!