So I can't lay down on either of my sides or on my back without feeling SUPER dizzy and like I'm…

So I can't lay down on either of my sides or on my back without feeling SUPER dizzy and like I'm going to faint but when I sit up my heart beats so heart that I feel like I am going to faint even harder... I don't even know what to do. I got 2 hours of sleep and I'm just so upset and exhausted and I feel so weak and dizzy.