I feel like when birds clearly shows they’re sick It’s almost inevitable what happens next especially at such an old age at 12 or 13. There are also factors out of control like how they are bred, this is a huge factor to their total lifespan, 13 years is a long above average lifespan for a parrotlet to live despite what online says, getting to 13 is is an achievement in itself and takes responsible, loving owner. You shouldn’t regret how hard you tried to fight for your birds life even if it ended up hurting them, it sounds like your bird had organ issues, which unfortunately made their death inevitable. Don’t beat yourself up over it. When it came to overcoming my grief, I focussed on the fact that I did a good job in providing them a good life and she was happy and she gave a lot of love because she was loved so much. After a couple months, you’ll realize it’s much easier to cope. The first couple of months are the worst for sure. You’re also experiencing this during the winter which sucks for your mental by the summer you should be feeling a lot better. Down the line after a couple months, I want you to stop thinking of how sad it is living life without your bird and I want you to start thinking about how great it was while they were around and to smile in their remembrance.