could you be allergic to chlorine??
Since you are showing these symptoms after entering the swimming pool,so it might be that you are allergic to chlorine or any of the contents of swimming pool. It has been reported that swimming pool water increases the predisposition to allergies and hay fever in swimmers. You can confirm that be getting yourself tested for allergies by an allergist. Skin prik tests and blood tests like RAST are employed to find if you are allergic to chlorine found in swimming pools or any other chemical in the pool.
If you face any of such symptoms again, please take an over the counter antihistaminic like Benadryl or zyrtec.If symptoms are severe, oral steroids may be needed. Also, if it is your private pool, then ask swimming pool manufacturers to replace chlorine with some other chemical to which you are not allergic.
If you sense any difficulty in breathing after entering the pool, then please consult an ER immediately as it can be life threatening anaphylaxis.
It is very difficult to precisely confirm a diagnosis without examination and investigations and the answer is based on the medical information provided. For exact diagnosis, you are requested to consult your doctor. I sincerely hope that helps. Take care and please do keep me posted on how you are doing.