Numbness n the left side of the head and diziness

Hi,
One evening about three weeks ago in London, i suddenly started feeling very dizzy and faintish. I felt i was going to pass out at any minute. I was short of breath and everything seemed strange around me. I was rushed to the ER but they found nothing wron with me. After weeks, same thing happened again and this time there was this heaviness and numbness on the left side of my head and i was struggling with breathing-as though there was a shortage of oxygen, i had to be taken deep breaths. I went to the hospital and i had all kinds of blood tests,24hours ECG and all what not and i was as healthy as can be, the only abnormality was that my BP was not as low as it should be when sleeping or in a state of rest. I was given a drug prochlorperazine to ease the dizziness. I am still dizzy and the heaviness is still there. I need advice