Nausea and swelling in hands

I went to drop something off at the dry cleaners at this plaza. Some of the stores there do sell foreign grown goods. I say this because my sister told me it may be an allergic reaction. However, I never went in any of these stores nor do I recall touching anything. Anyways, the dry cleaners turned out to be closed, so I turn around to walk back home. As I walked, I felt kinda nauseous. The further I walked, the nausea turned to a more painful, stomach ache. I got some coffee, by that time the stomach ache was fading...however my hands started to tingle. I stayed inside. Then the tingling feeling turned into slight swelling and reddening. My nose started to clog up even though there wasn't much mucus and there was slight difficulty breathing. My eyes started to water. After I felt itching around the neck, arms, back, and scrotal zone. The itching became really bad. I decided to head home. I took a couple of cold showers and it didn't stop. Finally after an hour after the itching began, it started to fade, and the swelling began to stop. I am currently at this stage. There is still some slight itching, my nose is starting to 'open up' again. I never had a cold or anything before leaving, it was 11 degrees Celsius out so it wasn't exactly cold. What happened? I didn't think it was serious, but it was really annoying.