What's the Name of That Book??? discussion

Its a Ya novel about a girl who falls/ is pushed overboard on her yachet during her birthday party and she comes back to the world of the living as a 'ghost'. There's a boy with her when she's between worlds and she doesn't remember him but he's actually the guy she hit with her car. They can go into each other memories by holding hands. The girl had an eating disorder and was always running. When she was a little girl her mom wouldn't let her eat peanut butter and the mom died in the shower. Her stepsister (?) was a redhead when she was a kid and she might have been the one to push the girl overboard. There was something else about her running coach and her boyfriend. The cover of the book was a picture of a girl sitting on a swing in the clouds with her head bowed.

Between by Jessica Warman.

Between for the click for Andria's suggestion.