What Causes Vomiting And Stomach Pain After Swimming In Pool Water?

4 year old went swimming all day, no issues where they were submerged or dunked...his diet was not optimal; ate only sweets and drank juices (capri suns, et al) and a dinner roll (no water, real food) immediately AFTER swimming (mind you, he was fine up until night fall), he began to gett irritable, insisted on going home. Started vomiting what loked like juice, he is getting a gurgle type heave when vomiting out something, now is dry heaving (refusing to drink Pedialyte- lethargic, says his head and tummy hurts-but he s a brat anyway so it s hard to determine whether it s his bad discipline or actually something worth noting) thinking it was heat exhaustion, swalled pool water? Fear of secondary drowning.