Weird sickness

I know this prolly isn’t the place for this but I’m quite worried

My bf texted me Saturday night saying he felt weird and woke up Sunday morning really dizzy and couldn’t keep anything down then Monday he felt better in the morning but the dizziness came right back with some nausea later on in the day he felt fine again and today’s Tuesday and he said he felt fine all day until about an hour ago the dizziness and nausea came back

What could be going on?

He’s had migraines before but he doesn’t have a headache