This is a tough week. Once the kids are back in school (assuming they're school-age) re-evaluate what is overwhelming you. Some ideas:
- More structure to the days they're off school
- Babysitters more often
- Finding ways to do less (not folding laundry, more takeout and/or easier meals)

I have one 4yo DS and I feel this way from time to time, and felt it constantly until about a year ago. It's tough, especially when you thought parenthood would be magical. Sending hugs, this sh** is so hard. Things that help me:
- a mental health day from work about once every 6 weeks (for sleep, hobbies, doing nothing, etc. - it helps me feel like myself again)
- at least one night away from parenting every 4ish months (overnight babysitter or grandparents)
- babysitter at least once a month for date night
- classes that break up one weekend day - DS currently does a dance class on Sunday early afternoons and while I have to get him there, it separates the morning and afternoon

I have three under four. Baby will only sleep if held. In the last week we've been to urgent care for a uti, pink eye, RSV and a stye. Nanny called in sick the week before Christmas, then we lost power for 27 hours. Then I got food poisoning.

The key is to disassociate.