Sick, nauseous and headachy. Have you had this bug recently?

[MulberryDerry]

High temperature, vomiting in children and nausea in adults, extremely extremely terrible headache?
Have you had it recently too? What on earth is it? Not flu (don't react to the light) and vaccinated.
The headache is horrendous

I had similar for about a week, tested negative for covid each time. It then suddenly felt a fair bit worse and tested positive for covid overnight. Ended up feeling quite poorly for a few more days after that, with 3 days pretty much stuck laying down and sleeping a lot.