Running errands or procedures and social phobia

I’m not sure if I’m saying or calling the following properly.
I’m referring to doing procedures with public administration offices and other institutions.
But, even more, it happens to me with many others institutions such as banks, doctors, some shops wherever I have to manage myself socially.
Lately, I’ve had having to do lots of this stuff. It means, telephone calls to make appointments or solving doubts, then, attending there and having to ask for things with the necessary interaction with people.

Of course, I have been delaying everything as much as possible due to the high level of anxiety it provokes me. What makes things worse because little by little you feel more unable to do things. You feel yourself incompetent.

At last, this week, and counting with the help that I’m feeling better of my depression, I’m been able to face to some of these processes.
And it feels so good, it’s such a relief that I even feel like celebrating.
I think the one of you who have problems dealing with social exposure are gonna be able to understand what I mean.

Wished I have more constancy at facing these situations.
I heard it helps to have a previous plan before each situation you have to face and you fear.
Do you do it? If so, how?