I agree with Dot there, sleepyj, insofar as when you are so low, you can only aim (even aiming at something can be a big shot...) at small things. I have been diagnosed with depression after being generally unwell (mentally) for a few months, and I know how it feels. No matter what people say, no matter how much you want to feel better, you just can't. It's especially hard if you have a naturally generous heart, as you feel guilty for not sympathising. All I can advise is talk to your GP, as mine was very understanding and gave me some pills which, not being a long term solution, make feel better nonetheless.
All the best! And as said before, try to find relief in the small things! It can be stupid, like watching You've been framed and have a few laugh, but laughing is the best therapy! xxx