Dd 13 missing lots of school

[unicornsrule]

It has been going on for ages she has missed alot of school!!!
She feels sick and retches alot so misses school.
She gets really upset if you try and get her dressed and lashes out.
We have been referred to cahms
As think it is a mental problem like anxiety and also now swaying towards it being autism.
It is starting to affect the whole family

My younger sister (14) is autistic and we had the same problems with lashing out and refusing to go to school.

The simplest thing sorted it:
Go to school every day for 4 weeks and we'll take you on a day out of your choice.
After that she just went.
Appreciate that's basically impossible now it's almost the holidays. The routine change won't be good right now either.

Are there any specific reasons she doesn't want to be at school?

No not a-tall
The treat reward sounds great

What other symptoms relate to autism?