Any ideas on what could be causing my hives?????

Last night while I was jogging, I got this strong tingly feeling once I started sweating then my entire body broke out in hives from head to toe. Even part of my face was affected, as my nose became rock hard and numb. I became dizzy and nearly passed out. I took some allergy pills and took a hot bath. Hives disappeared immediately.

For the past 2 days I had been drinking tons of soda flavored with high fructose corn syrup. Could I be allergic to it? But the thing is, I only get hives when I run at night. I do most of my running in the morning and have never gotten hives.

I had never had hives before until this year. I didn't change my diet whatsoever so I have no clue what could be causing it. I don't have diabetes as my blood glucose level is just 75.

Any ideas?