Baby Separation Anxiety

So I’m a nanny for a family. I have been watching the oldest for almost two years now, and the youngest ever since he was about 4-5 months old. He is now about 8 months old, and I’m running into a problem that I’m having a very hard time figuring out!

So baby has always been very comfortable around me–giggling, happy, etc. I went to watch him yesterday, and for the first half hour or so it was as usual. Then, suddenly, he’s super fussy and crying and not happy at all no matter what I do, and I did try everything in the book I could think of (checking diaper, trying to feed him, trying to distract/play with him, rocking him, walking outside with him, etc.). Nothing worked, and eventually I got him down to sleep (he took a bottle!) and chalked it up to maybe some teething and being tired.

Then today, I come over and the minute he’s handed over he completely throws a fit, cries, so on and so forth. Again, I try everything in the book, even so far as trying to lay him down for an early nap, but nothing works. Eventually I had to text the mom, and when she came home and held him he immediately was much less fussy. Obviously being with mom is preferred for any baby, but the thing that worries me is how badly he reacted when up until this point I’ve never had any problems. I am super careful with all the children I nanny, love working with kids, and I truly don’t know of anything I may have done to get this reaction.

I guess at this point I’m just looking for advice? I’m watching him tomorrow and I’d really like to be able to give the mom and break and not make the poor baby miserable! If anyone can suggest ANYTHING, it is greatly appreciated!!!

TLDR: I am babysitting a baby who I think has a bit of separation anxiety (?) and am wondering how to alleviate that as best as possible!