I have a social phobia and did something stupid. I need help?

I have a social phobia. I'm on payments so I have to work for the dole right now. I did it yesterday for the first time at a charity shop. I was very worried they'd have me working behind the counter but thankfully I was out the back sorting and tagging items. But today I'm pretty sure I was meant to be at the counter.. so I worried about that a bit.

Thesedays I seem to take forever when I'm getting ready. To anyone else it would look vain, but I'm so insecure that I just spend so damn long on myself hoping I'll look at least RELATIVELY okay. I'm never satisfied with the end result. Not completely. I have very low self esteem. I have depression but the anxiety seems worse these days. I don't feel 100% miserable all the time anymore so that's something. But I do feel anxious.

I have to walk to the store. It takes about 20-30 minutes. Suddenly I checked the time and it was ten to ten. I grabbed the phone immediately, planning on calling the shop and telling them I would be late... but then I couldn't think of a good excuse as to WHY I would be late. Then I just sort of freaked out wondering what to do (it sounds ridiculous, I know) and at some point I remembered I had another appointment at 11:30 with my employment service provider (who must've forgotten I was meant to be at the charity store on that day, otherwise he wouldn't have made that appointment). Feeling panicky, I considered just ringing them both and saying I was sick (and in the shop's case, insisting that I'd still be in tomorrow), but I thought that sounded really lame. I can't explain it, but it makes me feel like a ten year-old kid faking sickies and I didn't want them all to think I was being stupid and lying. This stopped me from calling anybody. Though I'm fully aware it looks just as bad not doing anything at all.

Another thing about me is, I'm scared when it comes to situations like this where I have to face up and use the phone. I'm generally an honest person but in this case I think the truth just sounds pathetic. I got freaked out so I didn't come in? It doesn't even make sense to ME, so why would it to them? I might be okay if it were JUST the store I hadn't gone to, but because I realised I had that appointment with the employment place, it's even worse. Because I truly believe the guy I have to see thinks very little of me and would just think I was wanting to get out of everything.

I want to try and call them now but I don't know what to say. I'd like to just say I've been sick, but why wouldn't I have called earlier if this was the case? I know, I'm an idiot. I'm worried about what I'm gonna do...