I have that feeling too - head rushes and getting dizzy when I stand up, pin pricks in my head and sometimes everything going black but my eyes are still open. It happens alot when I am squatting down or sitting on the ground and get up. I think it is definitely a blood pressure issue (my BP is normal too) but I don't know if it is thyroid or adrenal related. My doctor doesn't seem concerned by it but it the more research I do the more I think it is an adrenal problem in my case. I have been on 100 mcg of synthroid for 10 wks as well.
Is what you're feeling the same thing as what I "tried" to explain? It's really hard to tell people what the feeling is, but I do feel a little woozy at that time.
Yes I am on thyroid meds. I was just uped to 62.5mcg the other day
Are you on any meds for your thyroid? I've been on Levoxyl for about 6 weeks now, and I've noticed that when I stand up, a lot of times I get this "whooshing" sound in my head, where it almost feels like I can hear my heartbeat in my head. My BP continues to be in the low range (110/58), so I don't think it's high blood pressure. I have an appointment with my doctor on Tuesday, and will ask him about it. It's a strange feeling, that's for sure.
Lori