Must be something in the air, Jade. I had a meltdown yesterday on the way in to work (trying again, had a few good weeks ...) and had to pull over the car. Even then I couldn't bring it back down, certainly not enough to risk a day in work. In the end I managed to fetch in and told them I'd been sick on the way in (kind of true ...) so they sent me home.
So, it's very easy to understand how you feel about the book shop situation. That's not the sort of thing you shake off easily, especially as it was something that gave you so much. It might also explain why you're sensitive to the way this lass has been behaving. Even if it is nothing and you're seeing things through the lens of your experiences, it's still difficult.
Churches can be funny places, too. They're incredibly open to new faces to start off with at times. Everyone is almost effusive in their greetings. Then you become a familiar face and there's almost a sense of "job done" but where do you fit? In some respects that's when you find out how genuinely welcome the place is. Not to mention finding out how many members have as many problems as yourself!
I know you say that the docs are probably not going to be much use going back to (or even getting an appointment with right now ...) but given the symptoms you describe it might be worth it. I know that the last time I started making some of the comments you've included here I was told that this came under their heading of crisis even though I didn't think so myself.
In the meantime though could you please keep checking in here? Just so we can support you through this. Remember, we're crap at advice, don't have the first clue about how to manage mental health problems (mis-management ... now that we're experts at!) are about as medically qualified as barber surgeons and are prone to off-the-wall jokes that are about as amusing as watching Nadine Dorries gazing longingly at Johnson (okay, that is funny in a rather disturbing kind of way).
What we can do though is be here for you. Lend an ear. Help you sift through thoughts if you want. Talk complete and utter crap. Argue the minutae of Dredd until your brain oozes out of your ears. Whatever ...
Take care, pal.