Hi @Stopsnowing - I'm sorry to read that your DD is having a difficult time at the moment. I have an autistic DD14, and I know how tricky it is to know how to support your DD.
My advice is based on what has worked with my DD.
Try and work out what your DD is interested in. Her interests might be quite unusual (for example. I work with a teenage autistic girl whose special interest is fungus, and my DDs special interest is pokemon, and anything Japanese!), but don't criticise or judge her interests, just try to learn about them, so she can talk to you about them if she wants to.
Try to make home as non-stressful as possible. If she has chores, break them down into tiny chunks as open ended chores can be overwhelming for some autistic people (so if you want her to tidy her room, ask her to put all books away first, then sort clothes into clean and dirty, then put dirty clothes into washing basket, then clean clothes away etc etc) but consider a break from chores if she is overwhelmed and struggling to get things done. Anxiety is a common co occuring condition of autism, and the best way to support her is to remove perceived pressure and stress as much as you can.
Celebrate small achievments. When my daughter was struggling to get to school, I used to say 'well done' for managing to get her school uniform on, even if she didn't manage to get to school.
In terms of support groups, I did a course through the National Autistic Society on supporting teenagers with mental health challenges. It was a good course, and encouraging for me to meet other parents who were going through similar challenges. I'll see if I can find a link and post it below.
https://www.autism.org.uk/what-we-do/support-in-the-community/family-support
And some Local Authorities do courses as well - have a look on their website to see if they offer anything. My LA is rubbish and they don't offer anything, so it does depend on where you live.
And in terms of your daughter meeting other autistic teens, can you ask her school if they offer shared interest groups? (These are groups that are aimed at autistic students, but not exclusive to autistic students. Autistic people often find it easier to engage with people who have similar interests to them, so finding out what your daughters' interest is would be really helpful). Not all schools offer them (my DD's school doesn't) but it is worth asking. Also, have you talked to the school about your concerns? It is always good to have school on board adn to keep them informed. Schools are able to offer access arrangements for exams and put some reasonable adjustments in place without a diagnosis.
My DD has started an online Japanese class, and nearly all of the students on the course happen to be autistic!
And BBC Sounds has a Podcast called 1800 seconds on autism. The presenters are autistic, and they talk about different things every week. I listen to them to help me understand my daughter a bit better.
I hope that's helpful. X