What Causes Lightheadedness, Pressure In Ears And Dizziness?

I have been feeling light headed, pressure in my ears, ringing and crackling and a little dizze (like motion sicness, not vertigo) The malady comes and goes during the day. My concentration diminishes when I feel these simptoms. Also, I feel extremly sensitive iin my head, like if i have a headache but not quite. When I walk I feel the steps in my head. Some times I hear an eco of my own voice. It is soo bothersome. It is making my work day very difficult.