You're dealing with a huge amount of stuff there.
How you see yourself in your relationships with others.
How you think they see you and what you think they expect from you.
How you feel alone with your stuff.
And trying to make sure you friend stays alive, along with all the other relationships where you are supporting them.
That is a huge amount of stress.
Maybe shifting just one small part of things might help?
Whatever that shift is, it might lift some burden off you?
I was also the person who fixed everything and everybody. Until I felt like I was drowning and went into therapy, and slowly gave myself permission to allow others to sort their stuff out (mainly for me my family: they created their problems and I took a step back from fixing them). Felt weird and odd,but over time it is so freeing.
And I learnt that my friendships, to varying degrees, are also there for me (again, to varying degrees). I learnt to be able to express myself.
For now, maybe giving yourself permission to acknowledge that it is your friends job to keep themselves alive. You can be there to listen (but maybe there are also limits with that? And that's ok).
Just changing one part of it might help you a little?