Hello - please may I have some advice.

My daughter was diagnosed  with High Functioning Autism 2 years ago.  Since her diagnosis she seemed to be making real progress at school.  Her grades improved as did her attendance.  At the end of last term she, what seemed to be suddenly, felt that eating needed to be controlled.  Over a couple of weeks she lost weight and became very worried about herself as she was scared.  She said she knew what she had to do but she just couldn’t.  Fast forward through Christmas, as siblings returned home for the festivities it felt like we were out of the woods.  She is in year 10 and had been at her school since nursery and she likes it.  She has a few good friends, works hard and is much liked within the school community. She is very empathetic, polite and kind.  However last term she refused to go to school on numerous occasions- this resulted in about 15 days of not being in.  She is now feeling like she’s failed and has not returned for the first 3 days - I doubt she will get in to school tomorrow.  I am not putting pressure on her at all but I am very concerned of her lack of attendance as this is the crunch period for GCSE’s and she does not want to get behind. The school has suggested I get a GP Wellbeing Navigation referral but I also know how reluctant she is to speak with people - she only opens up to her immediate family and none of us are qualified to help her get back to school.  Any suggestions would be most welcome and thank you in advance for reading my post and for your advice.