How to manage if I get this flu?

I'd recommend making sure the medicine cabinet is stocked.

Broncho Stop cough medicine, packets of paracetamol, anaesthetic throat spray so you can sleep at night, some nasal rinse for your sinuses, strepsils.

Tesco Whoosh was also a god send when I had flu as could order every couple of days and have an order arrive in 45 minutes.

Yes this too. Last time the children and I were all ill we just camped out in the sitting room so I didn't have to move around the house to look after them

Make sure you've got plenty of simple food in the freezer and cupboards
Have a shopping delivery website set up.
Get to know your children's friends parents. I happily would help someone I didn't even know that well.

It's not fun being ill and caring for children but they will survive a week or so of benign neglect

I had a similar reaction to COVID first time we had it but luckily just for a few days. We got by with a lot of screen time, easy meals and take out that lasted us 2 days. I made a bed on the sofa and we vegged together. They were about 3 and 5 at the time. It wasn't ideal and it wasn't great parenting but we survived. My sister video called and chatted to them for ages at a time too, they took my phone about with them as they played.

Is your 7 year old able to prepare anything for himself? Even simple things like cereal or sandwiches, and juice/water etc.

Also, your DC's school(s) may be able to provide a pick up and drop off service if you do get so unwell that you're unable to get out of the house to do the school run. Obviously this depends on the area and their school(s) though. My son's school provides this service, obviously only in extreme circumstances.

Otherwise, I would keep them off of school and just request for the school work/homework to be emailed across so you can help them with it while you're recovering.

It's awful being a single parent with no support, especially when you're ill. I've been there many times (I have a good, strong, albeit small, support system now though).

Have you had the flu jab?