Roxy,
Good for you for doing 30 miles. Last time I got that squirrely on my electrolytes, I wound up in the ER - So Don't do it again!.

The ambulance crew that picked up Babs yesterday asked if we were the same bunch they ran on the last two sundays? Guilty as charged. One of their runs was for someone who was suffering from dehydration, as they were only drinking water. You need to drink some kind of electrolyte replacement as well. Please find something you like, and drink it as you ride. My current favorite is the Crystal Lite "hydration" - but there are plenty on the market.

I can get heat exhaustion pretty easily, and it's much better to drink the fluids and prevent it, than try to fix after a full blown melt-down. Trips to the ER get expensive too.

And don't save the electrolyte solution for "long rides" only. One water bottle of water, one of your sports drink, on any ride you'd be packing water bottles.