You didn't lose them, they just decided to go in a different direction. Not your fault! This happens at least once to all of us.
I just did an interview last night for the most adorable 1 yr old girl. The mom and I had a great chat and all went well. She just emailed me and said she would be making her decision on the weekend. I would love to have this F/T child, however, if mom choses another d/c I will not beat myself up over it as I know it was a great meeting and I wouldn't change anything I said or did. Another client will come along as one well for you because through this forum we learn from each other how to run our great daycares. Starting up takes time, so relax and enjoy your kids and the phone will ring.