Stress?

Recently, I have really experienced the might of stress. In one of the surveys that I have done about my personality, it says that I am a "perfectionist". After looking up the meaning of this word in the dictionary, Longman dictionary mentions that "someone who is not satisfied with anything unless it is completely perfect."I feel that this is really true as I always set high expectations of myself when doing things. However, for now, I am beginning to feel that things are getting out of the control. I have many problems hounding in my mind, Track and Field, Studies, Chess, Maths Olyampid. These are the three main problems in my mind.
I feel that I am beginning to grapple with my studies. I find difficulty in grasping certain concepts in content based subjects. I think I have to settle this problem by hook or by crook.
Another week has passed with intense pressure applied on my brain. I keep reflecting every night and day whether I have set the expectations of myself too high that I cannot cope or that I cannot achieve. There is one period that I am careless in doing things and I don't even know the causes of this. Careless is a weakness but cannot be utilised as an excuse. I have to eradicate and obliterate this weakness of mine. This will be a psychological battle with the careless virus within my mind. I know I can control it and I know I can deal with it by relaxing myself.