I think I might have covid

[Wednesdayafternoon]

So basically I have Covid or a cold.
Someone at home has Covid yet I've had minimal contact with them. They tested positive on day 1 of symptoms 5 days ago.
I've also had contact with someone who has a really bad cold and was sat next to them all day at work.
I started feeling rubbish on Friday, achy, feel sick, feel tired, irritated, blocked nose, eczema flare up... bla bla bla.
I tested fri and sat morning both negative. I will test tomorrow night. Due to start a new job on Monday :(
My question is, I know we're. It required to isolated but hypothetically if I tested positive tomorrow, would the recommended 5 days begin from Friday or the test date?

I'm personally of the opinion that if I'm positive id stay at home/quiet areas until I feel better but my family put so much overwhelming pressure on the rules and isolation, they'd have me at home for 14 days if they could! :(

I thought it was 5 days from when your symptoms started but I may be wrong.

I notified on the NHS app and it told me five days from the date of test

*Positive test obviously

Thanks all! Tested again this morning and it's negative and im feeling mainly better so im just going to assume it's a cold and stop testing now!
It's crazy how I've avoided Covid twice in my home but seemingly picked up colds at the same time 🙈