What Causes Loss Of Memory, Blurred Vision And Headache?

do i have brain cancer?or am i suffering from early stage of alzheimer?or am i worrying for nothing?or am i suffering from other but minor diseases?-my memories went from incredibly good to bad-and so does my eyesight-i am suffering from bad headaches (for years) that could lasted for days and become worst and more frequent from time to time-sometimes the pain strikes me in the head in a sudden although there is no pressure or radioactivity around-my studies were badly affected by the headaches because most of the time when i tried to read or focusing on something my eyes hurts and became blurry which leads to the pain in my head-i cannot memorize or understand anything in one page although i tried so hard to because it hurts-my hair is thinning-all of these started since i entered secondary school