AHH! Wierd cat scan press, please give a hand!?

Okay, so tonight I had to stir to the er for headaches i own had for days gone by 5 days, bad ones. they took a cat scan, short ink, and then told me i have some kind of abnormality, but 8mm surrounded by diameter, at the base of my brain in close proximity the spinal cord. I freaked out, I have severe anxiety. So after they did an MRI, they took some pics with the injected ink, and later some with the ink. They told me the mri can supply them more info about the mass. They come back and told me the mri is fine, it detected nought. I asked them what the thing on the cat scan be, and they said it was a "blip" doesn`t matter what that means. They said it be an "artifact" whatever to be exact. What is a blip? an artifact? They said i had nil to be worried about, and if they be worried then they would hold referred me to a specialist. I need to improve my mind. Oh, they diagnosed me with acute sinusitus for the headache. I think I am not compassionate what the docs told me, can someone out there backing? I am freaked out. Get a second opinion or see a neurologist. In the ER, on the spot life threats or instant complaints are what are treated. You ALWAYS need to follow up.
hmmmm cal me 555 6878