Dizzy after plunge

Hi

I had a 15 minute sauna followed by a cold plunge for a few minutes at around 12 degrees celcius. Towards the end of the plunge the room started spinning so I got out and sat down for a bit. I was dizzy for a few minutes and felt nauseaus for about 30 minutes after.

Could this be related to being too long in the sauna, too long in the plunge, or both?

Thanks