Repeated burnout from work

I should preface this by saying I'm not yet diagnosed autistic- I have an autism screening by my psychotherapist tomorrow and I've no idea of what the outcome will be but watching videos on adult female autism, it rings an awful lot of bells... If it does apply, then it's a 2 year waiting list on my local NHS for a diagnosis.

If it is autism, I'd like to know what can be done, if anything, to avoid burnout/serious depressive periods triggered by anxiety at work? I've had this happen to me 3 times- one time, I managed to get on an art course for a year which helped, then a couple of years later I spent around 7 years out of work (volunteered okay) and now I'm in another spell of recovery, this time, it's been almost 2 years (again, I'm volunteering for the sake of my CV). Generally, they've all been triggered by getting extremely stressed at one job to the point of depression and tears/ suicidal ideation, getting a new job and quitting then moving house for the new job and coming a cropper after about 3-6 months after the initial excitement of a new start has faded. 

My CV looks dreadful because of it. I'm 43 and the longest I've held down a paid job is 3 years. I'm not going to move house again for a job as the change seems to be a major factor But I'm genuinely scared of what will happen when I come to apply for full time/30 hour week jobs again and the inevitable downwards slope. I can't volunteer for ever- what can I do?