My hands were a little itchy last night. Went to sleep but couldn't sleep. Got about an hour of sleep and when I woke up my hands were very swollen. Went into the bathroom and felt incredibly dizzy and flushed, my face felt tingly and I felt very close to fainting. Then I started to feel nauseous but never actually vomited. I can't think of any medication or insect bites in the last day or so. What's going on?