hi, my name is shiro. I have been feeling really sick and need to know whats wrong. I have blurred vision, fatigue, loss of appe

I feel really dizzy when i stand, i've been trying to read a book i bought but i can barely keep my eyes in the same place for a minute. Sometimes i feel like my head is tense...and my eyes are straining. My sister says that i dont eat well but the whole reason comes down to lack of appetite. 

i try to eat a balanced diet everyday...my breakfast is whole wheat bread with a cup of tea and orange juice, for lunch i'll eat mostly canned beans and rice and dinner is optional, pizza or chicken.....what could i possibly be suffering from. I take a vitamin everyday too.