Then if your diagnosis of burnout is correct (and I'm not doubting you for a moment ) it looks like you've never given yourself a chance to recover?
I'd tentatively suggest:
1. Significant time off. Use this time to rest, heal, exercise, and also to focus on dealing with any interrelated issues - such as depression.
2. Critically analyse your lifestyle - is there anything outside work that you're doing (or not doing) that's contributing to your apparent continual downwards direction? (Google 'Tignum book' - might give you starting point.)
3. Think about the job you really want, and what characteristics it should have? e.g. if regular/routine interactions with colleagues are a problem, would remote working, or night shifts, or a more solitary role, help?
I never really took time between jobs. Maybe a week or so to take care of paperwork for the new job.