Can you tell the ex you’re full of cold/think you have a migraine coming on? Tell him it’s help if he could keep the kids tonight and drop them at school tomorrow?
I know myself that no amount comments on here saying go for a walk/just have a shower/text your mum/ring your gP will help in all honesty.
sometimes I just have to wait for something in my brain to click, and the motivation comes back.
give yourself permission to be kind to yourself, do the bare minimum, do whatever gets you through - go back to bed if ex can look after kids.
if kids come home, just focus on bare minimum. Everybody fed (beans on toast?) and everybody in front of the tv, sofa time til you can get them into bed.
tomorrow, when they’re at school resolve to do just one thing to get you back on track. Pots, or similar.
sometimes if I put one put in front of the other, pull myself through the sludge, it sort of gets me going on the right track. the motivation slowly starts drip drip dripping back.