You probably got overheated. Symptoms:
weakness and light-headedness
What would also indicate this, is the fact that the cold water snapped you out of it.
Calm down, it's not going to happen again out of the blue. It may never happen again your whole life and if it did, this time you'd know it was heat exhaustion. Take steps if you feel heat exhaustion setting in to avoid it. If you still feel the need to see a doctor, have your wife go with you.