I had to go the pharmacy yesterday and was standing in line for about five minutes behind a mother and her child. I didn't pay them any attention until the mother was talking to the pharmacist and I heard her say "chicken pox". When I looked, the child had lots of vivid red spots and was scratching.
Please tell me I'm worrying about nothing. I can't remember ever having had CP before and my parents are away so I can't ask them if I've had it.
Chicken pox is highly contagious but spread by coughs, sneezes and coming into contact with the fluid from spots. So I think you will be OK if you were just stood behind the child and they didn't splutter over you or give you a hug. It's not like you were down at their level, chatting to them.
Although this is a reminder why parents should avoid taking chicken poxy children out and about - you never know who you might come into contact with and how you might be compromising their health.
Op context your gp or midwife as they can test and give you a treatment if it's within ten days of the exposure. The nhs pages advice is very good. It says close contact ie face to face contact or being in a room with someone for more than 15mins
The vast majority of peoole are immune Btw even if they don't remember having it as a child.
They don't check CP immunity as a matter of course. I was tested as had never had it as a child and there was an outbreak at school. Turns out I was already immune, as most adults have been exposed to it even if they never caught it. Ask your midwife for a test.