That is because you are too focused on doing it "right". That was something that I also had problems with in the beginning. Anxiety went away from the moment t

That is because you are too focused on doing it "right". That was something that I also had problems with in the beginning. Anxiety went away from the moment that I've read and accepted that there is no right or bad way to being mindful or meditate. Also not being negative against bad feelings that could arise when practicing and just observe was a big step for me and made it easier to make it go away or make it less powerfull.