School Attendance Officer telling me my daughter's attendance is poor

I received an email and spoke to school on the phone, and really did not like their tone. My daughter is Autistic and doesn't eat a balanced diet, is a picky eater, doesn't have an ARFID diagnosis or anything similar, this badly affects her immune system. The way they said to me every months twice she is off due to fever, well fever is a natural response of the body when something isn't right. Even if I send her in and do what some do just dose the child with calpol her fever will spike again and I will be told to go collect her. She has been spending all her time in the bed or sofa and not able to do her usual activities the past 3 days, today a little active but not much. So I have spoken to Health Vistor to consult Child Development if she can be referred back to dietitian or something and beein trying to win the GO lottery to get her checked and her blood test forms so she can get her bloods done whenever they have an appointment at the hospital as kids isn't a walk in. I am actively following all guidelines as given by her previous dietitian, I have attended numerous courses, workshops and meeting in order to support her better including with her relationship with food. I'm not sure what else they expect me to do, make a deal with the devil???