When my husband got home, he asked how long she'd been that way (not long), and asked if she had a temp. I didn't think so but he took her temp with an underarm digital. (She wasn't feverish.) I felt around on her belly and she didn't flinch or complain, so I don't think it's her appendix, but it could be menstrual cramps... I gave her some Motrin and she's much happier now.
It's really hard when we can't ask her questions and expect detailed answers. She's a lot more verbal than many autistic kids are, so we actually have an easier time than some. But it's still a little frustrating and sometimes scary when we don't know what's wrong and she can't tell us.