Is something wrong with my purple firefish?

I have a 29 gallon tank I've had her since march she's always been shy. But she would still come out from behind the rocks and swim sometimes. Two weeks ago I decided to switch from crushed coral to sand. So all the fish were in the bucket for at least 6 hours before I was finally able to put them back in. She was doing really well. But yesterday and today she's been laying on the rocks on her side a lot or under them. And she's being very strange. I put the net towards her and she swam away. And now she's in the same position I haven't seen her eat either. Is there something wrong and what could I do to fix it?