My DD1 started refusing school aged 12 because she was terrified there. We tried punishing her for refusing. It was the worst thing we ever did. Please don't make the same mistake. I will never forgive myself for the damage I did to her in those early days.
She was diagnosed a few months later with Asperger's Syndrome. With the right treatment and support, she eventually returned to school and is now doing brilliantly in sixth form and working on her personal statement for uni.
I realised one day that, if someone stood me at the edge of a precipice in abseiling gear, it wouldn't matter how much someone offered me as an incentive or threatened to fine me for not going over the edge, there would be no way I could do it. All the pressure would do was make me feel more of a failure.
I stopped pushing my DD to the edge of the precipice and allowed her to choose her own route down. It took a lot longer and lots of people stood by shaking their heads in disapproval but she got there and is now ready to do the next journey alongside her peers so I know we got it right in the end.
Work with your DD. Let her know that you are there to support her. Allow her to take the lead and don't push her to do things that she doesn't feel able to cope with. Pushing her may be counter productive because it makes her feel more anxious and less able to push herself.
Sit down with her and make a plan together. Allow her to be in control and make every step small enough to be manageable and achievable. If she achieves something today, don't make her feel that she has to do that thing again tomorrow, otherwise she will be scared of trapping herself by making progress.
Also, you know her best. All strategies do not work for all children. Work with the professionals to find the ones that feel right and don't be afraid to say if you think something will make matters worse. You will probably be right.