Hi Loopyme,
Currently there are 2 main types of treatment - medication and talking therapy.
I believe that in depression cases, where it has been going on for some time, the best results come from a combination of both. As you have been on 2 SSRI anti depressants (prozac and citalopram) you could talk to your GP about either Mirtazepine or Duloxetine as these work in a different way.
If you're getting nowhere with your GP, either try a different GP in the same practice or ask to be referred onto more specialised services.
There are some things you can do to help and these revolve around trying to get a routine going everyday (not easy I know when you your motivation and energy levels are low) but sometimes reviewing the basics like your eating and sleeping patterns can help too. In addition to these points I personally found exercise a huge help for my symptoms and am very grateful I have my dog as he has been a big part of helping.
Hope this helps
Take care
Mark