Most likely caused by anxiety over your exams, and possibly being distracted by life at home and family problems.

Eyes - Some say that the eyes are the windows for the soul. Eyes symbolize perceptiveness, personal outlook, clairvoyance, curiosity, and knowledge. They also reveal information about personal identity and suggest to the dreamer what he should pay attention to.

Blood - Life's energy source. Love, passion, anger, and life itself. A vital part of our physiology and it may symbolize our strengths and weaknesses and our physical, emotional, and/or spiritual energy health. If you are currently experiencing a very difficult time, or facing a difficult decision, in your life, you may have dreams with bloody or frightening images. Don't worry, you may just be venting your fears, and emotions.

Water - represents your subconscious, your emotions, and your accumulated life experiences, and the flow of 'feeling' energy. It is also a symbol of new life, refreshment, vigor, energy, cleansing, emotional stirrings, fertility, growth, and creative potential.

Green - has always stood for vegetation and nature. Green is growth, connection to nature, and innocence. Also, peace, tranquillity, the Earth, and money.
Dark green calls up a negative attitude towards life, exhaustion, breathing difficulties, tension, sleep disorders and paranoia.
Bright green refers to overwhelming emotions.
Green that is soft and pleasant stands for relaxation, contentment, sensitivity, hopes and self-confidence.

If the young boy is completely unknown, he would represent your younger and inexperienced self. Depicting your feeling anxiety about your exams.

I hope this helps to allay some of your fear. Best of luck on your exams!!