AIBU to ask if there's anyone who knows much about potassium levels?

[JetTail]

I've been to A&E twice over the weekend. Friday my potassium was 3.3 (slightly below normal range). Saturday it had dropped to 2.5 (dangerously low).
No vomiting or diarrhoea.
Is it relatively normal for the levels to drop dramatically?
What could be causing it to drop?

Are you on diuretics? They can cause it.

Also Conn’s syndrome?? Don’t know much about it. It’s seen in cats sometimes.