Work and autism

I’m currently off work to care for my daughter who has autism and I have the second part of my diagnosis today. Every so often life becomes too much with the demands of everyday life and I *** down. I’ve been like this now for the past 2 months after my daughter took an overdose, all I want to do is keep her alive and I feel I’m very focussed on this part of my life. The issue I have on top of that is work are calling to try and get me back in and have tried every avenue to do this, the problem is they are horrific to work for and I can’t cope with it anymore. If I was to be diagnosed no changes would be made and I would be expected to do the same job which has become impossible as I have *** down to it now. Can I just leave a job if I get a diagnosis? I don’t feel as though the way my life is anything or anything type of job is suitable at the moment!!!