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The symptoms could be due to diving for first time, too high or too low oxygen or due to claustrophobia. Please get this investigated once. Hope this helps. Take care!
Bends (Nitrogen Narcosis) would involve deep or extended dive times, but an air embolism can happen in just a few meters of water. A fever is a sign of infection not associated with PE or N2 Narcosis.
COBOB has provided an excellent answer. You don't have to dive deep for this to happen. You need to see a physician who knows about diving immediately.
As for sharks, for purposes of trivia, the Glock pistol is the only one with an accessory enabling it to fire underwater to protect yourself against sharks.