What Causes Head Pressure With Lightheadedness?

Hi, I have been having some anxiety attacks and I was wondering if my symptoms that I'm having right now is normal. I am feeling pressure in my head and feeling lightheaded on my left side. One ear wont pop. Sometimes I feel like I may faint. I am constatnly worrying that I have a brain tumor or cancer or something horrible like that. I also am having some short term memory loss and a little bit of confusion. Could this also be because the doctor told me to take Clonazepam?