Am I being too sensitive?

We've been ttc for over a year now. We've done two cycles of Clomid without success, we'll start our third dose (150mg) in a week or so. I went black Friday shopping today with my family. They don't know where ttc. It's a sore subject for me to discuss. I was almost out of prenatal vitamins so I picked up a bottle inconspicuously. I checked out first and the cashier looked and commented on everything I bought. When she rung up the vitamins she looked at them for a few seconds and then asked me if I was pregnant. I was shocked! I didn't know whether to scream or cry. My family was right there and luckily didn't hear her. Am I being overly sensitive? I just keep hearing and seeing pregnancy things all around me and its all I can do to not break down and then this lady asks me like it's any of her business. I think I'll do the self checkout from now on.