Advice on staying strong with a baby in the hospital

Any mommies have a preemie who stayed in the hospital for a month+ ? I'm having a really hard time with my babygirl being there and not home. I see her progress but it's still not healing this emptiness I'm feeling and nothing will. My bf doesn't seem to understand how I'm feeling eventhough I've talked to him. I keep having guilt and idk how to make it go away 😥