I shared a meal with a friend and was a little queasy and achy the next week. Meanwhile, she spent 3 days in the hospital with ecoli and is stil recovering.

It's possible you had the chicken pox, but your immune system kicked it's but early on and you didn't show many symptoms.

Go to your doctor and ask for a titer test. It's a blood test that will tell you if you have had chicken pox or not.