I would talk to someone directly. You sound very unhappy.
I wasn't quite clear if the problem was the work or the company? It's something that needs to be dived into and had a good look at because there could be imbalance in your life leading to depression. So you need to look at things like diet, sleep, exercise, relationship etc. It's possible you need to rebalance - it's possible you need a new career. A career break should never be a hindrance to a new job, and should often be a selling point, as long as you've used that time sensibly.
So in short, talk to a career coach or counsellor. Try and get some more face to face help. You say you work for a big company - they often have help lines for employees run by third parties - use it!
I wasn't quite clear if the problem was the work or the company? It's something that needs to be dived into and had a good look at because there could be imbalance in your life leading to depression. So you need to look at things like diet, sleep, exercise, relationship etc. It's possible you need to rebalance - it's possible you need a new career. A career break should never be a hindrance to a new job, and should often be a selling point, as long as you've used that time sensibly.
So in short, talk to a career coach or counsellor. Try and get some more face to face help. You say you work for a big company - they often have help lines for employees run by third parties - use it!