I have a little girl who is similar now. What I started doing was leaving her on the floor with the others while she is crying. When she stopped crying, I would pick her up, give her a hug and a kiss and tell her that she was a good brave girl. I would then put her back down to play. I only pick her up when she is not crying now. I will do this for the next while until she is settled. She also only started three weeks ago.