Convinced but can't get diagnosis

Hi.

I am new to this forum and was after some advice really. My daughter is 14 and is very affected by anxiety. I have always recognised some differences in her from the 'norm', since the day she was born (she had extreme separation anxiety and could not go to sleep on her own till she was 2 years old, amongst other things). However, she is an extremely bright girl and has never had any difficulties at school. She is at the top of the top sets at her school and has never misbehaved. The structure of school seems to really suit her and all her (many) behavioural difficulties have always happened at home. 

I had a lot of particular difficulties with her when she was a toddler, but I tried to manage them on my own, probably because at the time I thought Autism and Aspergers were learning disabilities, and apart from the emotional and social aspects she was a very clever kid. I believed she didn't have ADHD too, having read up on it. So I tried to deal with her the best I could.

Around the time she was in junior school things were getting much worse. I had recognised she had a real social awkwardness and she was having some major issues with other girls in the school to the point that she seemed to only have one friend and she was obsessive about her. If that friend was not at school she would have a terrible day. As it was I used to collect her from school and she would have been so wound up during the school day her emotions would spill out on the way home, leaving her distraught by the time we got home.I started to realise, too that she had always had various obsessions which included some compulsive behaviour, she was very literal with speech and action, she didn't like to look strangers in the eye, she had difficulty speaking to people (especially adults, including teachers), she was anxious about noisy environments and particular about things she touched that 'felt funny' (including always being fairly particular about clothing choices). She didn't seem to be like the other girls at school, or her younger sister.  At that time I started to talk to other mums who had similar problems with their (ASD/Aspergers) children and they said that my daughter sounded just like theirs, so I decided to seek medical assitance for her.

She took a lot of convincing that she could do with some help, because she couldn't cope with the idea that she wasn't 'perfect' - one of her issues (she has impossibly high standards for herself and a very poor self-image) but I took her to the doctor and was referred to the child psychologist (who thought her problems were all to do with my recent divorce - despite her having ALWAYS had them, since birth, and she was 11 years old!) who then referred her to the Child and Adolescent Mental Health Service. It was very difficult getting support from her school as they didn't think she had a problem, being that she was their star pupil who just sat and got on with her work and was never difficult at school (even though she spent breaks and lunchtimes just walking round and round the playground on her own). The mental health consultant did an assessment on her for ASD and ADHD and concluded after two meetings that she just had 'high anxiety' and could do with some anger management techniques. He suggested that she write a diary keeping a record of all her meltdowns (and there were many) and the reasons for them, and punch a punching bag for 45 minutes whenever she felt the 'red mist' descending. He gave us a sheet suggesting some similarly inappropriate things to do to deal with her feelings and, although, he made a follow-up appointment for three months later, we felt he wasn't really interested in giving her the help she needed.

My daughter walked out of the office and flatly refused to do any of the things he recommended. She couldn't cope with the idea of writing down her 'low points' because her anxiety and poor self-image would have only got worse doing that, and the idea of a 'ladylike' (that's how she saw herself) 11 year old girl punching a punching bag was insane. 

She refused to go to the follow-up appointment and we have not been back since. However, things have not really improved that much and I am really worried about the future. I am all but convinced she has some form of ASD/Aspergers from talking to many people who have experience, either with their own condition, are parents of children like my daughter, or work with children like her, and yet I am struggling to convince her to go and get a second opinion. The last three years I have dealt with her issues by assuming she has the condition and managing her anxiety and her behaviour accordingly. It has been generally okay and she has coped better than she had before. However things at school are now kicking up a gear as she is entering her GCSE studies and stressing out big-time. I am really worried that she is not going to be able to cope with exams, deadlines (she has a BIG problem with time management) and pressure. 

I really want to be able to take her for a second opinion but (assuming I manage to convince her it will be a good idea) I don't know how to go about it. I guess I am also needing to know if I am doing the right thing in pursuing a diagnosis for her, or if those of you who are experienced with this think I am barking up the wrong tree. I would really appreciate some constructive advice and support.

Thanks