Now, I only have it when quite severely depressed. I can't stand the sight of myself and I don't want anyone seeing me. If it develops into something less severe I still have these problems, but it's rather easy to overcome eventually. I don't do much other than exposure.

I used to have it for delusional "reasons". I just couldn't. No anxiety or panic. Hard to explain, but I'm pretty good at not explaining, rationalising. It didn't happen always, but sometimes. Antipsychotics helped immensely (I also considered it likely that I was being observed (rationalisation: using cameras at home. End of rationalisation), so it wasn't always easy).

As for the fear of panic attacks, realise that people that don't know panic attacks aren't likely to feel or see you panic much, as long as you keep up appearances. Same with the start of psychosis (which is not dissimilar). You might tremble a bit, but otherwise it's quite possible to appear pretty much normal.

Focusing on that (and not on actual or possible reactions, your own or those of others) also helps to lower the anxiety. Try to control your breathing, so you don't start to hyperventilate. Sit down slowly as soon as you can, but if you can't just stay upright. If you sit and might be hyperventilating, don't stand up or do it very slowly.

I believe there is only one way to deal with anxiety: exposure. Not exposing yourself to what causes anxiety (such as staying inside) makes things increasingly worse. And you know it.

Try to expose yourself to the anxiety while listening to (different) music. You have to desentisise so look for visual or auditory stimulation. If you don't fear moving crowds as much as passing just a few people or one at a time, or if it's equally distressing, expose yourself to the former.