What to say when people congrats you after mc

Jenny • I have an angel from December 2013, a baby boy born December 2014 and now tcc for a sister or brother after the sum!!! ♡
I was 12 weeks pregnant when I lost my baby. I had a lady tell me today she heard I was pregnant which I am 7 weeks but she don't know I lost the first baby and I'm waiting till my next appt to tell people. What should I respond to people?