My depression was and is always accompanied by anxiety. Like you even though the depression is under control, the anxiety still lingers. The only way I am able to control it is with medication. I take 0.5 mg of Alprax. I have never been able to get relief through breathing or visualizing unfortunately. I think my body is so used to reacting to anxiety that it is almost a reflex. I've had anxiety attacks all my life.
Not good news, huh?
Anyway thought I'd share this in case it helps