If you could smell chlorine, then the activation and strength were probably fine. Everyone is different ... depending upon where your body has the most pathogens, you may experience different detox symptoms.
Be grateful that all you got was a little nausea. You may want to cut back a drop down to 8 - 10 drops, then go to 3 x per day. Starting at 11 drops is NOT the best idea, and when detox finally catches up to you it might hit with a vengeance.
You may actually INCREASE your cold symptoms for a while, due to die-off, so be prepared for that.
Slow and steady is the mantra I keep repeating here ... 8 drops (or 10 drops) 3 x per day for several weeks is better for body cleansing than 15 drops for a few days, and will do a lot more for ridding the body of pathogens.
And it MUST be accompanied by super hydration (a liter per day per 40 lbs of weight), and more alkaline eating.