Very sensitive/allergic to chlorine (asthma and skin rxn) swallowed some pool water at practice; started coughing up phlegm and then threw up. bad??

It may be: Immediately, you have to worry about your throat closing and not able to breath. However, if you're writing this, I believe enough time has passed that you don't have to worry about this. Watch for signs of an allergic reaction, itching, swelling, a rash, runny nose/eyes or trouble breathing. If any of these develop seek immediate medical attention.