Did you go just once? Maybe it is a case of just repeating regularly to reduce the anxiety. I've read feel the fear and do it anyway and she suggests that the first time you do something new and move out of your comfort zone you will be really nervous but it will reduce with practice (I'd say particularly if you are doing challenging thoughts as well).
Well done on going for the first time in a year.
Well done on going for the first time in a year.