What Causes Weird Sensation In Head Along With Tunnel Vision?

I have had the rainbow blood work, head, chest, and stomach scan with dye. All they found was low potassium which I took pills for two weeks. They say I have anxiety and i take medicine for it. But, I still have a constant weird feeling in my head, sometimes my arms go numb, I get tunnel vision and feel like passing out. Could it be they have missed something?