Mare just lost her foal and now she's acting completely out of character?

Our one mare, Sadie, just lost her foal, Sisco, to pneumonia. Before this, Sadie was the sweetest horse I've ever met. She always let herself be caught, she was the first one up to see us, she was just a genuinly nice horse. Ever since Sisco's death, she's been standing off alone, away from the herd, she only lets herself be caught on occasion, and even when she's being ridden she's a lot more difficult. I've heard its not unusual for mares to act out of character after their foal dies but I was wondering if anyone knew how long this lasted, and if there was anything we could do. Thanks