Welcome to the forum,we are very glad that you found us and I am sure you will find the support that you are looking for.
Raising kids is so hard, and I am sorry that you are having to go through this.
I am not sure what state you live in,but there has to be some type of resource to help you with your children.
For your daughter and her self injury here is a great place to start...www.selfinjury.com/index.html
For your son,I would suggest talking to your family doctor on getting him into some type of therapy... your doctor may suggest that he goes into some type of hospital to get the treatment he needs. If he is under 18 then I would really consider admitting him. He might be mad at the time,but he will get over it.
Please take care of yourself,and keep us posted on what is going on.