What made us feel ill?

[Eino Maki]

Hi to All!
My buddy and I started diving in the fall of 2002 and in Jaunuary 2003 went to Cozumel and had a fantastic time. This last spring, we wanted to try diving locally. We each purchased an new 80 cu.ft. tank and went to his cabin on Deer Lake, east of Taylors Falls. We had on wet suits but no hoods. It was cold. we kicked up a lot of sediment right away. 20 minutes later, we were both hanging onto the dock trying not to hurl. For two days I felt like I used to after I rode the Tilt-a-Whirl at the fair with my kids.
We wondered if there was something in the new tanks that could have made us sick. I talked to the folks at the dive shop and they said it was probably a reaction to the cold and vertigo due to the silt and the resulting loss of visibility. I guess we sort of lost the reference to the horizon.
From your experiences, does this sound like a reasonable explanation? Have you had similar experiences? We have since purchased 7mm hoods but I have not had a chance to dive anymore this summer.
What measures can we take to avoid this happening again?
Thanks!
Eino Maki