Couch's spadefoot illness/injury?

[Nakantia]

Hi! I'm new here and new to the world of amphibians (being more of a lizard girl...)

I rescued six spadefoot tadpoles from a dwindling desert pond, and they're now toadlets from one to two inches in length. They're living in a large plastic carrying habitat with a mixture of Repti-sand and some of the sandy soil from the pond area (I rinsed it in spring water and dried it in the sun so their substrate is dry). They're mainly eating flightless fruit flies but are starting to eat very small crickets.

This morning I found the largest of them flattened like a pancake and squirming around in circles. He tried to drag himself forward but seemed to be weak on one side and kept going in circles. He flipped over a couple of times but was able to right himself. I managed to get him out of the habitat and placed him in another to get him away from the rest of the toadlets, and he seems to be doing better. He's not flat anymore and he's moving normally, but he still seems to be acting odd -- he keeps lifting his head like he's trying to look at me.

Has anyone seen anything like this? He definitely wasn't trying to burrow -- there was something wrong with him. The toadlets do sit on each other -- they usually make a toad pyramid when resting -- is it just possible that he was squished? I don't want to put him back with the rest of them until I'm sure he's not ill.