The "7 year" things is just an old wives tale. A person's allergies can change at any time, as I am living proof. What do you use to clean with at home?

Talk to your doctor, describe what happened, and get an Epi pen to keep with you. Describe how to use it to a trusted set of coworkers.

And yes, a "delayed reaction" is standard - your body attacked that "threat" with tons of force, and it takes a while for all that to dissipate. It can take a couple days for me to "clear" from a bad episode.