I know what it's like to feel worn down from a long days work and it's easy to feel sorry for yourself, but right now if you're in the city and still in your job you probably should be counting your lucky stars not feeling sorry for yourself.
It all comes down to perception and attitude - two people can be in the exact same circumstances and one can feel fortunate and the other one down on their luck. It's certainly true with health - there are some people with serious health problems who feel lucky to be alive and bring a positive attitude to facing their conditions, and others who may actually be in reasonable health but still find something to complain about without taking any action.
I don't want to be a total polyanna and say you can deal with anything with a positive mental attitude - there's obviously a strong genetic factor in numerous health conditions - but I do think people generally would benefit from recognising the positive aspects of their lives and taking more responsibility in fixing anything they're not happy with.
It's not even that difficult all you need is a pen and paper:
1. Write down everything you like about your life and everything you're grateful for ... Give yourself some time to think and include little things like 'pancakes for breakfast' and 'a lie in on the weekend' - the list may end up pretty long.
2. Write down everything you don't like and aren't happy about. Be honest here - still the list probably won't be longer then 1 - your glass is already more than half full.
3. Next to every item on the second list write down an action that you could take towards fixing or improving that problem. Start with baby steps where possible rather than big actions so against something like 'I want a flatter stomach' 'do an abs class once this week' rather than 'exercise for an hour a day' or against 'I don't like where I work' list 'review my cv' rather than 'get a new job'.
4. Set aside an hour or two on the weekend and tackle as many of the actions in list 3 as you can. As soon as you take action you'll already feel less negative about that item.
Keep working through the actions and repeat step 1 once a week until you start to feel like a genuinely happy puppy.