My iPhone 5s has stopped functioning entirely

For the past week, my iPhone 5s has experienced battery problems. It either ran out of battery (from a full 100% charge) in a matter of minutes, or just died without explanation when at a high percentage. When it shuts down, it goes to saying in needs power to turn on, so when I do it says I have the same battery percentage as before. This had been grinding until today, when I got back from a trip away from home. I sat down, watched a bit of YouTube, when my phone shut down. I put it on charge, and still was saying it needed to be charged. I left it for half an hour, and it still said that. I took it off charge for half an hour, stuck it back on and it is doing the same thing. I’ve changed the cord, done all the checks, held the power and home button for up to thirty seconds, nothing I say working. I need my phone for tomorrow as it holds everything I need in my project I am trying to complete, my music and all my notes. ****, I a, having to use my little sisters iPad to write this. Can anybody help please?