Stuck on an island with your BFF! (Zombie Apocalypse)

Everything was good, the end of high school was near, you were in your classroom talking with Sarah your best friend since childhood, you two have known each other forever and she has developed feeling's for you far greater than friendship since middle school

While talking with her during lunch, everyone in the school hallway heard someone scream, you and some other guys went over to check and when you guys got there you saw that the school's security guard was standing there with blood on his mouth and the principal was on the ground with blood flowing from his neck, it was clear that he bit him, suddenly one of the guys went to check on the principal but when he touched him the principal lunged at him and bit him too, horrified you and the remaining guys ran away , one bite led to another and now the school was filled with zombies walking around

You somehow managed to take Sarah and some of your class in the storage room along with some teachers and locked the door, everyone was horrified, after hours of hiding you and everyone else sneakily jumped out of the window and climbed out of the school walls by helping each other, once you were outside you saw multiple dead bodies, burning cars and zombies walking around

You guys ran away and somehow got to the sea port, your teachers got an idea that if they go to an island which is inhabited then the zombies won't be able to reach them,you guys got on a both and started the engine and one of your teachers started driving the boat towards a big island which wasn't far,after a day you guys were able to see the island, it was still far but it still gave you hope of survival, suddenly the weather started changed, it started raining heavily, strong wind started blowing and tides started hitting your boat, as a result the boat turned upside down and all of you fell in the water,you where the only one who knew how to swim so you grabbed the persons hand who was closest to you in the ocean water which happened to be Sarah, you tried to save others but they drowned, you and Sarah made it to the island

Sarah is panting heavily after arriving on the shore from the near death experience of drowning

Sarah: our classmates...... our teachers they are dead she starts sobbing uncontrollably and says while crying

Sarah: what do we do now? we are stuck here.....I don't want to die...