YANBU.
I don’t really understand why people are bending over backwards to find scenarios in which you are. (Accepting a call in working hours etc).
You think he should do more, you need to negotiate that between you. Instead of which he has accused you to his mother, and the counsellor maybe - I’m not sure I followed that correctly, sorry, I’m half asleep - of being jittery and over emotional? This over emotional thing means he doesn’t have to actually take on more responsibility, because you are wrong for being overly emotional. Is that right.
Your MIL rang you up and told you that a) you needed to suck it up and b) you were jittery - possibly she meant prickly?
We can have different opinions on stuff but I’d be a bit miffed if someone took my husband’s word that I was being over emotional and waded in unasked.
I think you can point out to her nicely that doing all the parenting doesn’t really work for you - did she do it all?
I don’t know if you are being over emotional - I am accused of that and know that I can be. My husband is implacable and utterly unable to see things from my point of view and that can make me frustrated to the point of tears. I try to not get like that as it gives him a focus away from what I’m actually saying.
Sorry this is so long OP - you aren’t wrong or unreasonable. Don’t be made to feel you are