Post Nasal Drip or something Worst?

Almost 3 weeks ago I felt faint and dizzy in the middle of the street. My throat felt as if it was closing up on me and my body was so weak and shaky. I thought it was an allergic reaction to seafood that i had eaten 15 minutes prior to that. The ambulance came and took me to Roosevelt hospital where they did the usual blood pressure and temperature and found it to be normal. I was still feeling sluggish inside so the doctor gave me a benadryl and said it was just food allergies. After this happened, i returned home and the feeling continued with shortness of breathe and a feeling as if someone were choking my throat. Not to mention i had a cough prior to that about 2 weeks ago. so i made an appointment to my doctor the next day. He gave me the usual check up and said it was a bad case of hayfever. He said my nasal passage was swollen as well as my tonsils. He prescribed me two drugs, veramyst(a nasal spray) and singulair(a pill). I have been taking these drugs and still am. That night upon returning from the doctor, the feeling came back and it was hard for me to breathe. My heart was racing (could have been shock or nervousness) my throat was closing. I beeged my mom to take me to the emergency room and this time we went to long island college. They put me in cardiac arrest, ran tests on me, and everything seemed normal. They brought an ENT down to stick a scope through my nose and check my throat. He said it was post nasal drip and that the mucus was spilling into my throat. So i was released from the emergency room and continued to take the medicine i was prescribed. i was feeling better for like 2 weeks until recently. Yesterday, i felt faint and nauseous and wanting to throw up but i couldnt. i took a 2 hr nap and woke up feeling the same way. I used the bathroom and my stool was green but my stomach was making weird noises and still felt funny. i took a few sips of antacid and water and it didnt really help. I went to bed with the same choking feeling in my throat again and minor chest pains. It's like shortness of breath, tight chest, and weird stomach feeling. Today i used the bathrom and my urine was strong, hot, and eally yellow. I also feel weak and have no appetite whats so ever. Can you please tell me whats wrong?? Does this all fall under post nasal drip and severe allergies?? :(