influenza
"My husband came home from a conference with a (cold), so I was hoping not to get it.  Went out of state for Spring Break, when on the first day had fever and chills.  I knew it wasn't a "cold", so immediate went to local urgent care.  Was diagnosed with flu (no swab) and given Tamiflu and a Vitamin B12 shot.  Took first dose and threw up within 2 hours, woke up with a headache, but otherwise, didn't feel horrible.  Progressively got better, and was actually able to enjoy my trip.  I'm better than my husband, who's the one that gave it to me!  It's a lifesaver!"