Tela, sounds like you struck lucky with the allergy doctor knowing what it could be. What kind of exercises did they give you? I have one which is quickly breathing in through my nose and then pursing my lips and blowing like through a straw out in 3 puffs.
I can completely relate when you say your anxiety set in deep when it happened. It's a horrible thing. When i am having a bad day my head runs away with thoughts that it can't be that and it must be something else and i just can't get my mind off it.