So, I've been having this thing happening where when I lie down and close my eyes, I start feeling this pulsating sensation and a little dizziness, like a tightness in the back of my head. It comes and goes, especially when I'm breathing in and out. It usually goes away after a bit, but I'm not sure what's triggering it. Sometimes I don't feel it at all, but other times it'll happen while I'm just sitting too. Also, I have an anxiety disorder, and my heart rate usually stays between 80 to 90 bpm. Does this sound like something I should be worried about, or is it more linked to my anxiety?