Stress has become a common feature for many people nowadays. The very reason for this stress is the lack of confidence or aiming at a very high level. For example I have to get 99% marks in the examinations is you goal. So you always think about 99% only. The thought process will continue. Instead of that if you think you are able to get 70%. Aim at 75%. In my case I never put any target myself. I always used to think exam are coming. I have to write well. Another technique not to have a stress is to pluck low lying fruits first. In the various chapters of subject. which chapter you feel easy and interesting, finish that first. It will build up your confidence. Lack of confidence is another reason for stree. I may not be able to do concept is not good. I can do concept is the best concept.
Another way of coming out of stress is to change frequently the subjects. You will have 3 or 4 subjects. If you study the same subject continuously you get bored and you can't concentrate. So rotate the subject once in 2 hours or so. You will have good interest.
Set achievable goals
Pluck low lying fruits
Don't study the same subject continuously
Don't expect any outcome. Do hard work.
Your stress will comedown