I'd do technical writing. Maybe instead of aiming for FT, aim for a few bits of contract work. Then use those to burnish your portfolio (or start one.)
Advantages of technical writing:
1. You get to spend your time playing with things, asking questions, talking to engineers, and, therefore, learning.
2. Depending on what you're writing, you may get to do some coding along the way.
3. You make a valuable, urgently-needed contribution to the world, for even when they can write, most engineers don't write, and the result is that most workplaces are saturated with so-called 'tribal knowledge.' Not only does this waste an engineer's time (explaining and re-explaining how a thing works,) but it also means that people who fail to ask for or receive help never learn how a thing works. This has all sorts of knock-on effects, monocultures and ingroup/outgroup dynamics among them. Yet you can write this fate away, if you can find an employer who recognizes the importance of documentation.
4. Which is not to say you'll be recognized or celebrated. Writing, these days, is a humble pursuit. But the impact you have will be significant, even if no one traces it back to you, and that can be be its own satisfaction (and also, résumé talking point.) And helping change the world for the better -- even just a tiny part of it -- can greatly improve mental health.
5. Once you get in the swing of writing, apply it to your stress/depression/anxiety (or however you want to characterize it -- that feeling.) Keep a journal. I know this feels like being given a teaspoon and told to excavate a cavern --- your mental health struggle sounds like it has its roots in life challenges that are genuinely stressful, rather than the putative 'chemical imbalance' sort of anxiety/depression. And a pen is no magic wand -- it cannot erase your debts, or restore your sense of ease.
But it can open up a bit of wiggle room. A space to turn the thoughts around.
I also recommend long walks and cooking.
6. When you're feeling a bit better, start applying to more jobs. You can do it. Signed,
A currently un-depressed ("pressed?"), non-anxious ("enxious?"), and happily-employed engineer, who was not that way 12 months ago.
P.S. talk to a therapist. IANAT, IANAD.
P.P.S. if you're not already on them, and your doctor thinks it's ok, take antidepressants. They are symptom relief, but again, you're looking for wiggle room.