I never knew that making scripts was an aspie/autistic thing until I got diagnosed. I just thought it was normal "thinking before you speak."
I'm living in Japan right now and I have to plan EVERYTHING I say because I often literally don't even know the right words so I have to piece together what I want from vocabulary I have and hope that it makes enough sense that I can get what I need.
Interestingly, in Japan it's considered bad manners to engage your customers at checkout. The idea is that everyone is busy and their personal lives are none of your business so don't hold them up with small talk. I bet you'd like it here ^^
But being here and being illiterate and only able to speak and understand about half of what goes on around me has taught me a few things. For one I am totally not afraid to write down notes of what I want to say to someone and if I get frustrated or hung up I will literally just hand them the paper. I call it (and this sounds terrible when you translate it to English) "White Privilege" which is where Japanese people automatically assume that because you're white you're a dumb foreigner and can't figure anything out on your own and they're just going to have to do it for you anyway. So it works out for me because even though I usually get hung up more because of the social anxiety than the language, I never have to explain that to anyone and they just automatically help.
I also do that thing where I get worked up for days over something and make it into a big deal in my head. I write these lists of things I want to do each day and I have this trick where if I don't finish the list, I recopy it onto the new day. That way I'm always aware if I keep missing something or putting it off. If it happens too many times in a row I break it down into smaller easier chunks.
For example in Japan you don't donate your used clothes, you sell them to "recycle" shops who sell them for money. It's really embarassing because, for example, I sold 3 sets of business outfits that I grew out of (Yup. 30'somethings grow out of their clothes. It's called getting fat) and had to wait for 10 minutes while they evaluated them. I was offered $0.90 and $0.20 for two pieces and zero for the rest. You're all, "Wow. I'm wearing rags that literally are worth less than rags."
But because I knew this was going to be stressful, I broke down selling my clothes into 1. just walking past the store. And after I did that 2. I sold my *business clothes* because I knew they would be the best received and be the least likely to get rejected or get told that I shouldn't sell garbage or whatever (how do I know what's valuable? I'm getting rid of it!). Now that I know what the process looks like and I've been successful once, 3. I'm ready to go back with the rest of the pile. This whole process has taken me a month because I need to recover between each episode.
So...maybe you could make yourself a list of what you have to do to successfully pick up your book? And then you could practice by doing the easy parts first and then working your way up to the scarier parts? And if you had your script, too, then you'd be all kinds of gold. Here! I'll write you a sample script!
GROMMET: Hi. I ordered a book?
LIBRARIAN: Oh, hi, sweetie! What was the title of that book you ordered?
GROMMET: [Say the title].
LIBRARIAN: Ok, let me get that for you, hun.
GROMMET: Thank you.
<Librarian returns with book. You stand there waiting.>
LIBRARIAN: Is there anything else I can help you with?
GROMMET: No, thank you. <hand her your library card>
LIBRARIAN: <Takes card. Swipes. Prints return receipts etc. Hands things to you> Ok, you're all set! Have a great day!
GROMMET: Thank you.
Variations: Librarian might not say "sweetie" and "hun" because she might not be from the American South. She might ask for the author instead of the title. She might not find the book. This is probably the worst variation because then you have to *do* something different.
Contingent plan:
...
LIBRARIAN: I'm sorry, hun, we don't have that book here. Are you sure you ordered it to this library?
GROMMET: No, I have to double check. Thank you for your time.
<You go home and congratulate yourself for doing a Hard Thing>
Because it is a hard thing to go out and do this stuff! And if no one can understand how hard you worked and cut you some slack for it, you have to do it yourself. My awesome therapist taught me that. She said that it's important to recognize your own accomplishments and reward yourself for doing them. She never told me I had to compare myself to other people. She was like, "look, cooking yourself food and eating three solids in a day is an accomplishment!" So give yourself credit!