Dear L.,
I know, there must be some help for you. Firstly, do you think that she is too young for Kindergarten ? Even if her birthday is the 'correct time' for your school district. Maybe you could have her stay with a group that is only about 4 or 5 children this year. like a mommy babysitter who takes care of children in her home. Pick a low key mommy if you do and visit the place - of course, you know that. It won't hurt her to stay out of K. for this year. It may help in a lot of ways - like finding out what is really bothering her. It will take a lot of pressure off of you and your family too, so that you can spend this year getting her on the right road to being peaceful inside herself.
Also, high praise for calling about mental health. This could be something serious. I was a preschool teacher and had a little boy about 3 1/2 with a terrible temper like that too. He did the same thing and finally quit. One day he started his tantrum again, so I just took him into a room that was not used often, and let him have a whale of a fit - tantrum, yelling and cursing and crying and snot running out of his nose, he threw chairs and tore papers off the wall. I just stood back and was there to help him not hurt himself. After a loooooong time, he quit and started really crying. I put him on my lap and cleaned him up and asked if he wanted to go out to play. He nodded and so we went out of that room hand in hand. We went to the water fountain, he was so short that I held him up to the water, and then he got a huge gulp of water in his mouth puffing out his cheeks, I just knew he was going to spit it on me, so I asked him if he could spit his water over the fence. He did. then he got some water to drink and we walked around the yard together and he decided it was time to ride a tricycle, and he did that peacefully. In the next few days he was a lot calmer, and finally wanted to go home to be my little boy. I almost cried. I still think of him often and wonder how the rest of his life has been. I found out later that he was not a welcome child because his mother's parents and gr parents did not 'like' his daddy. What a burden for a child. Anyway, I am sure that is not true with you, but you can see how children react sometimes when they think that they have a problem that they don't understand or of course do not know how to solve.
I hope that you and your family can work this out and get peace back into her soul.
Sincerely, C. N.