What Causes Head Rushes With Floating Sensations?

In the last six months I have had 5 episodes lasting 5-6 secs where I have a rushing feeling starting at the back of my neck surging in to my head and then down to my feet leaving me with a brief floating feeling for a few seconds. I have a patent foramen ovale and have suffered a tia once. Not sure if related. Right now I am suffering from vertigo perhaps related to an inner ear problem. Not sure if any of this is related to these episodes. I have had a recent ct that came back clear just in case a blood clot traveled to my brain.