T.K.
When I was a single mom, I had an infant and a toddler and a teenager. I had to do as much as possible before they woke up and after they went to sleep.
Get up, brush my teeth, makeup, hair, etc. I would get myself totally ready before waking them. Then get breakfast ready, and wake the kids up. feed and clothe them and out the door. Drop them off.
I tried to get as much done at work, as possible. I would try to grocery shop or run to Dollar Store for supplies on my lunch and on the way to pick kids up.
Then pick them up, get home, start a load of laundry, feed, bathe, play with kids. Pick up around the house. Kids to bed. Then choose outfits for the next day, pack diaper bag and backpacks. Wash dishes, more laundry.
Then sink my butt on the couch to watch tv.
I love how people say being a sahm is the hardest job in the world. Not even close. Being a single working mom is. You have to do all the same houseowrk, cooking, cleaning, shopping, running errands as a sahm. PLUS figure out how to pay for everything, PLUS be the disciplinarian, mom and dad all at once, PLUS satisfy your boss and prioritize work. When a kid gets sick you're torn between being able to nurse them or support them. It's so hard.
My suggestion is to get a back up sitter that doesn't keep any other kids. Like an older woman. That way you don't have to call in everytime your child has a fever.
And keep a box of redwine in the fridge for emergencies!