Hi, it's definitely a menopause symptom I've had it on and off, I'm really not sure what truly causes it, I've had it mostly under control but had a recent bout of it returning after increasing from 3 to 4 pumps of estrogel , it went away when I reduced back to 3 so that comfirmed it was too much estrogen for me, but to complicate things I've also had it on too low a dose of estrogen, its finding the right balance I guess, I hate the feeling though its hard to explain and I too felt on the verge of panic when it happens, I think it's a really common symptom so you are not alone with that feeling, hope it goes away for you soon as it is a horrible scary feeling, for me too it was worse in the morning and wearing off by the evening x