It's great that there was a time you felt better. I know that it's probably really frustrating that that didn't last when you got home, but it does show that you do have the potential to feel better - so although things seem hopeless right now, maybe they won't always.
When you say that you're achieving 'nothing', I don't think you're giving yourself enough credit. You're not achieving nothing. You're in so much pain, and yet you're still here, you carry on getting through each day. I always see you posting pics of your cats and it seems like you take really good care of them. I know it's incredibly hard to keep doing these things, but you deserve to give yourself some credit for it. It's not nothing, it's huge.
What is it about the support in hospital that helps? Sorry, I know that probably sounds like a really silly question! But if you can break it down a bit we might be able to help you think of other ways to achieve the same result.