What Causes Sudden Imbalance Of Body Along With Dizziness?

Hi I had a brain aneurysm rupture Decmber 9 th 2012 followed by bacterial meningitis .Another aneurysm clipping Janurary 2014 and another aneurysm stent and coils October 2014 and was doing fine until Janurary 3rd 2015 and all of a sudden got dizzy . had a cat scan done and all looked fine so the neuro dr thought it was vertigo and sent me to a ent and the only thing I failed there was when I close my eyes I fall back so he recommended PT to see if it helps . I m just not sure what is causing the balance and dizziness problems?