Mindee hasn't been himself today, very lethargic and emotional and just curled up on the sofa.

I didn't want mum to worry or leave work early because mindee is happy being curled up here, but mum will be here soon and I'm worried she'll be annoyed that I didn't tell her...

I would just say exactly what you've said here. It's not enough to warrant calling her home but you thought you should let her know. Maybe next time a quick call or text just so she knows.

If no temperature or other obvious signs of being ill, I wouldn't necessarily phone. Especially if it isn't really affecting the care you are giving the others.

Might just be tiredness. Did you have them yesterday? Might have had a full on weekend and if with Mum a busy day yesterday.

I agree if there is no real signs of illness I would either send a quick 'just to let you know' text, or just fill her in at pick up time xx