Apologize to her and support her now. Honestly, it’s the biggest thing. I have a broken relationship with my mother, but it could be mended in half a second if she really, truly, just accepted who I was, faults and all.
Are you working with a neurologist or teen psychiatrist? If not, I definitely recommend you get one. I like developmental pediatricians and neurologists better than psychiatrists, but a psychiatrist will do. Working on medication, not only for ADHD, but for her anxiety, is a must!
As for the self esteem, get her in with a good therapist. That will help and alert you if she’s considering anything dangerous. Beyond that, celebrate her successes and try not to focus at all on the things she has to try again with (I hate calling them failures). Also, if you can, go for an IEP at school, not just a 504. You can easily request this in writing by giving the principal a handwritten letter that says no more than, “I would like my daughter, Name LastName, to be evaluated for special education.” That will get the testing process going. If she needs as much help as you say, she’s likely to get the IEP.