Htc m9 overheating

[AC Question]

So a few days ago i charged my phone overnight, as i usually do. But in the morning, the phone was burning hot and now my battery life depletes far too quickly. It will be 100% and not even 20 minutes later (of just sitting on my desk) it's down to 80-75%. I went to bed pretty late that night and woke up early, so the phone wasn't on the charger any longer than it has been before. Could i solve this with a new battery? Should i get a new phone? I have only had this phone for 3 months, never had any issues with it before.