Misery....Can anyone diagnose?

So I wake up this past Friday morning with my whole body covered in hives. This pic of my underarm should give you an idea of how miserable I was. I know I had an allergic reaction to something I ate or ingested (per 2 doctors, 2 pharmacists, and 1 speech path), but I can't figure out to what. I didn't do anything out of the norm, but something brought this on in a hurry. Any ideas???? On Thursday night I ate Chex Mix (some say the spice in it can cause this)...
I quite taking Zyrtec that week (some say it could be something in the air)...
I went to a party at a house with a strong candle and dog there (been around both a million times)....
I took a bath in a dissinfected bath tub with BBW bubbles (done this a million times too)....
I just can't imagine what set off this horrible reaction.

5 days later, 2 shots down, 1 box of Benadryl consumed, and a half of steriod pack to go....I'm finally feeling better.