Advice needed

Can anyone advise me on how to help my 17yo daughter. She has an ASD diagnosis but no EHCP as she was coping with school until last year. She struggled in her GCSE year with the additional pressure from school - we cut back on all demands and she managed to keep going and get her GCSEs.

In September she started college, studying for A levels and all went well at first. But over the Christmas holiday she went nocturnal, not going to bed before 3am. Not getting up until mid-afternoon. And now she’s struggling to get to college at all. Every day there’s a massive emotional wrangle to get her to get up. She says she can’t. She wants to but can’t. Is this burnout?
The GP is inaccessible - it takes weeks to get an appointment. She had a blood test to rule out thyroid issues etc and we are waiting for a follow up. She won’t see a therapist, won’t try sleep hygiene / relaxation techniques and won’t accept any responsibility for her own actions. It is everyone else’s fault that she can’t get up.

It’s reached the point where she’s barely going in and looks set to drop out entirely. At the same time she says she loves college and wants to go. How can I help her?