I feel like this too. I can only liken it to how small babies must feel when they are utterly over-stimulated. The constant being on-ness and noise is burning me out. The DCs are bickering constantly, bored, their behaviour is deteriorating, they are becoming very resistant to the home learning, and I'm really struggling to balance everything.
Today (well, yesterday) was a definite low point. DH is working Mon - Fri so I, as the lower earner and self-employed, am fitting my work around him. This means the odd bit of work admin or actual work during the week, then I do what I can over the weekend. I only manage maybe two hours across the working week due to the DCs and the nature of my work, which can't be done in the evenings and requires a lot of setting up and packing down. Tomorrow I am working out of the house, but today I needed to work from home. I told DH days ago this was the case and that he needed to be on parenting duty all day to facilitate this. He got up, mooched, decided to go for a bike ride (left whilst I was upstairs getting dressed), had a leisurely breakfast upon return, then a long poo followed by a shower. When he finally came down it was lunchtime. He said he hoped the kids hadn't been bothering me too much and that he'd take them out for a trip to the car wash... Afterwards he still didn't actually do anything to entertain them, just stuck the TV on, so they were still under my feet and constantly demanding my attention as they were bored. Unsurprisingly an argument ensued. He still doesn't understand why I'm fucked off. I now feel awful as the DCs overheard me shouting that of course they'd been bothering me, because that's what they do (because they are small children, not because they are awful kids) and that's the reason I'd asked him to keep them occupied and away from me. Not my finest moment, but I'm at the end of my rope.
He had also earlier made a remark about how it felt like a lovely lazy Saturday, which probably didn't help. Not for me is doesn't! I get 5 long days of drudgery, skivvying, childcare and school work, followed by 2 days physical labour. He does 5 shortened work days, 2 family days where there is no pressure to get anything done and often me around to lighten the load, and more 'free time' than usual to cycle. I've had enough.
We had a big discussion a couple of days ago that I was overloaded and burning out. We agreed to some small changes that would really help, including him doing a couple of adult-led activities with them each week.
DH this morning: did we? Remind we what we'd decided?
ARGH!
He's usually pretty good at pulling his weight, although has always been awful at remembering conversations/decisions, but doesn't seem to understand he needs to do far more than the usual at the moment even when it is spelled out in the clearest terms.