To think partners don't always realise how hard mat leave can be?

[Nicknamegoeshere]

So I've just spoken to my fiancé on his lunch break and asked what time he's coming home from work. I have three kids - two older boys (with my ex-husband) and a six month-old baby with him.
Obviously we are in lockdown too so I'm on my own for most of the day.
I just asked him if he could do his best not to be too late as I start to flag around 6.30pm. As usual he has left his Christmas shopping until the last minute.
He replied sarcastically "Ah poor you."
AIBU to be annoyed by this response?

Tbf it's not as if he does nothing as some are insinuating. He does all of the cooking, for example. He gets up with her both weekend mornings so I can have a couple of hours more sleep. He walks her in the evenings. He takes my eldest to school every day.
I just wish he'd realise that I am also "working" if that makes sense?

i previously held a very senior role in a multi-national, was pretty much on call 24/7 and would work 70hours+ a week (on a good week). I stopped work to be a SAHM. Hands down, SAHM is harder work than my previous job. The lack of mental stimulation, the drudgery, the lack of proper sleep, the loneliness, the anxiety of not knowing if my baby would sleep, eat, be well was bloody horrendous. You need to carve out some baby free time where he steps up and you step out. Don't take no for an answer, get this sorted asap. In addition, if you are planning your return to work then you both need to start working out how the home obligations will be managed. Devise a task list and allocate it out to him and you. Don't get lumbered with being the maid servant/cleaner/primary carer. Forewarned is forearmed!

Yes tbf I am looking forward to my return in a work in a way. I'm not looking forward to the evenings, however! I imagine I will be working well into the early hours!!