Well... I'm certainly no expert, with regard to these sorts of things. However what occurs to me reading your post is that, given the level of anxiety you describe, perhaps the best most immediate solution would be to talk to your doctor (whoever prescribed your antidepressant) about additional anti-anxiety medications you might try.

There are lots of techniques for calming mild & even moderate anxiety. But it sounds as though you're really struggling. Plus... you've tried at least some calming techniques & they haven't helped. It's great you're going to be seeing a therapist. And, over time, that may help. But sometimes, at least as an interim measure, medications are the way to go. Perhaps this is one of them.