Hi Tukella
I can empathise as I am diabetic and suffered from depression after the death of my wife.
My best advice would be to keep things as simple as you can to take some of the stress off yourself. Set goals that you can achieve. In that way you start to feel better about yourself. That becomes a self-reinforcing cycle. Incremental steps that sitck are better than large ones that don't. Improve, consolidate and improve again. Life is a bit like dancing; take it one step at a time.
I've been given a couple of British Heart Foundation publications about diet and healthy eating. They are; Eating Well (Healthy eating for you and your heart) and So You Want To Lose Weight ... For Good. They contain some good information to use as a baseline. I firmly believe it's about eating well generally rather than sticking to one diet or another. They seldom work, or if they do the effects are short-lived.
If you are looking for a good way to record your diet, including sugars, take a look at Myfitnesspal. It's simple to use and gets easier the more you use it. The book, Life and How To Survive It, by John Cleese and Robin Skynner is a good read if you like self-help books.
Hope this helps.
Ray