One of my awesome coworkers provided me with a pack of Guatemalan Worry Dolls! According to Guatemalan folklore, when a child has a worry all he or she needs to do is sleep with a worry doll beneath his or her pillow. The worry doll "does the worrying" for the child, so the child can then sleep peacefully.
I have not yet had a student take a worry doll home, but I did have a student carry a worry doll in her pocket for the whole day. This student was worried because her puppy was having surgery that day. Before I gave her the worry doll, we had a discussion about the worry and we decided that if she worried about her puppy all day, she would not put her best effort into her learning! This student was very concerned about her schoolwork, so she decided to let the doll worry for her. At the end of the day, she returned the doll and said that it made her feel better and get through the day. I highly recommend this easy intervention for K-2 students!