I actually remember a lot from the story except the title/author.
It's a case fic. While Sam and Dean are investigating a haunted house, a spirit pushes Dean off the stairs and he falls through the rotting floor, landing in the basement. He's seriously hurt and Sam has no choice but to take him to the hospital. Dean has either a broken leg or a knee injury. Sam befriends a nurse and he accidentally uses all her change for his soda.
The boys have a motel at first but, because of Dean's injury, they eventually stay on the nurse's Aunt's property. While in the motel Dean is in such pain that Sam double doses Dean with his medicine.
Someone is snooping around the Aunt's property (turns out he was a land surveyor or something), Dean freaks out and wants to pack up and leave. Sam "accidentally" trips him up making him fall onto the sofa.
It took place around the time where Sam had abilities because a beer bottle was flung towards Dean, who was sitting on the porch. Dean thought the bottle had been thrown by Sam in a fit of anger, but it wasn't.
Sam falls for the nurse and she somehow is involved with their original case. She sees Sam handle the ghost while she was riding her bike home from the hospital and she freaks out.
At first I was thinking this was part of the Drive 'verse or the Fusion 'verse, but I don't think so anymore...maybe.
Any help is appreciated. Thanks. :)
ETA: Found in comments... The Lee by pdragon76. :)