What Causes Headache,blurring Of Vision And Loss Of Hearing?

I would just like to know if I have a serious condition or another problem with my health because whenever I am sitting for long periods of time (or lying down), when I stand up my head starts to pound, my vision either fades or goes completly, I get a strange feeling in my hands and arms as if someone was poking me with ice cold neadles and my hearing sometimes goes. Please help