Humidity is pretty high. Some of my balls won't eat when the humidity is that high. Others won't eat unless the humidity is high. They can be strange creatures...

Could be entering a shed cycle, they'll do that occasionally when they find new homes. Also wouldn't hurt to get a fecal done just to make sure she's healthy on the insides.

Also, do you trust the person you purchased her from? There's always the question "Why are you selling a breeding size female?" especially when you get her home and she won't eat.

3 weeks isn't a long time, 3 months and I'd start to worry. I will say that all of my females are back on feed tho. Keep trying and good luck!