I've had these since I hit puberty. They can be scary, I sympathise! Mine aren't related to anxiety (I have plenty of that too but there's no correlation for me personally!), but they are indirectly affected by hormones. I get particularly low blood pressure in the run up to my period and at other times of hormonal disruption, and my ectopics are caused by the low BP. Paying more attention to hydration, and making sure I don't get too hungry or tired usually helps. I hope you find a way of managing them.