There’s a lot of viruses going around because everyone is immunosuppressed from covid. You can have multiple infections simultaneously. There was a tweet recently from someone whose nasal PCR in hospital came back as covid, RSV and influenza. Which would suck.

So it’s possible you don’t have covid but caught from them something else that makes you feel dogshit. If that is the case good news you’ll feel better faster and are less likely to have post infection complications.

However you can also test false negative early on. If you can afford to test in a couple days you should. Brand doesn’t matter, whatever is cheapest. You should rest and keep contact with others to a minimum. Even if you don’t have covid don’t spread what you have.

If you do test positive and there’s any chance of antivirals get them, these are expensive privately but many different places have funding/programs for at risk infected, embellish your history if you need to. Antivirals make you recover faster, have less risk of dying or getting long covid.

If not possible and it is covid. Rest as much as possible. Like actual sleep rest, not inertia on a computer or in front of a TV. Don’t exercise either.