What attracted you to your first job when you graduated? What attracted you to your degree? I know you're very dissatisfied with work and have had depression, so it might be difficult to answer, but if you look at all the separate tasks which make up your job(s), now and previously, there must be some which you enjoy, or at least don't mind - and equally, what things could you absolutely not tolerate? Every job has an element of boring admin and so on, but so you can't avoid it all, but certain jobs will have more than others.
Think about what makes up a job. Do you want set hours? Would you do shift work, on-call, weekend work?
Do you want to work in an office? Always the same location, or moving to client sites? Work from home? Travelling for work, being away from home?
Do you like working with customers, clients? Face-to-face, on the phone? What about colleagues? A small team, or big department? Presentations? Problem-solving? Planning? Creative? Logical?
Look at things you find easy - that often means it's something we're good at rather than it's something than is easy for everyone. When you're looking at strengths and weaknesses, try to be objective about them - if you're not good at something, is it lack of training/ experience, or something where your strengths really don't lie? It can sometimes be hard to tell, if your sight is obscured by the cloud of depression. You can also ask friends and colleagues what they think your strengths and weaknesses are - it won’t always match what we think about ourselves, and that can be helpful feedback, too.
Think about the practicalities - what's the lowest salary you could do with to maintain your current standard of living? How does that change with a shorter or longer commute and associated costs - not just petrol or train fares, but if you need more childcare. Can you relocate easily? Do you have any physical restrictions, e.g. if you had to stand all day, or do a lot of physical activity?
If you think about all these things - and many more - what interests you, what really doesn't - you'll start building a profile of the sort of job you want, and then you can look at what job types fit it, and then you can see what training is needed.