Emergency situations symptoms and conditions

Hello, my name is Rob and I have been on Remicade for the past 5 years. I had a reaction to my first Infusion, shortness of breath and feeling flushed. They then added Benadryl to all future infusions and everything has been fine until this last infusion in April of 2008. Halfway into the infusion my face became flushed, the person adminisitering the Remicade said it was hives, this was accompanied by tightness in the chest and headache. They stopped the infusion, gave me some Benadryl added to the IV, that did not work, they then added Solu-Medrol 125MG into the IV and it seemed to reduce the effects of my reaction. The infusion was completed and I went home. Upon arriving home I looked quite pale until that night. My face became red, almost as if I spent too much time in the sun and I have had a headache followed by chest pains. This condition has continued into the next day but it does not feel severe enough to go to Emergency. Should I be concerned or will this pass? Is it possible that I have been on it so long that I am now building up a tolerance to it?